Excess mortality and cause-specific deaths (2015-2025)
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From: SPENCER JONES
To: Stats NZ – Official Information Act Officer
Via: FYI.org.nz
Date: [Insert]
Tēnā koutou,
Under the Official Information Act 1982, I request the following information relating to excess mortality and cause-of-death trends in New Zealand, covering the period 1 January 2015 to the most recent data available in 2025.
This request asks for numerical, aggregated data only.
No identifiable personal information is sought.
⸻
1. Annual total deaths & excess mortality estimates
For each calendar year: 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, and the most recent published period for 2025:
1.1 Total registered deaths in New Zealand
1.2 Age-standardised mortality rate
1.3 Annual excess mortality (number and percentage) using Stats NZ’s standard baseline methodology
1.4 Any internal or published technical notes describing how excess mortality was calculated for each year
⸻
2. Weekly mortality (2015–2025)
Please provide the following:
2.1 Weekly total death counts (all-cause) for every week from 1 Jan 2015 to the latest available week in 2025
2.2 Weekly baseline model used by Stats NZ for “expected deaths”
2.3 Weekly excess deaths (or sufficient data to calculate this)
⸻
3. Cause-of-death by ICD-10 category (2015–2024)
For each year:
3.1 The total number of deaths for each ICD-10 “Chapter” category, including but not limited to:
• Neoplasms (C00–D48)
• Circulatory system diseases (I00–I99)
• Respiratory diseases (J00–J99)
• Endocrine/metabolic (E00–E90)
• Nervous system (G00–G99)
• External causes (V01–Y98)
• Mental and behavioural disorders
• Infectious and parasitic diseases
• Ill-defined causes / symptoms / unknown causes
3.2 Mortality rates (crude or age-standardised)
3.3 A copy of any annual or quarterly “cause of death” statistical tables held by Stats NZ that may not be publicly displayed on the website.
⸻
4. Specific categories of public concern
For each year 2015–2025, please provide:
4.1 Total deaths classified as:
• Sudden cardiac death
• Acute myocardial infarction
• Stroke / cerebrovascular accident
• Pulmonary embolism
• Myocarditis
• Pericarditis
• Aneurysm or aortic dissection
• “Ill-defined or unknown causes” category (R00–R99)
4.2 Total deaths coded under the following cancer subcategories:
• Acute leukaemias
• Lymphomas
• Metastatic cancers with <3 months between diagnosis and death (if recorded)
• Pancreatic cancer
• Brain/CNS cancers
If Stats NZ does not hold the “diagnosis-to-death interval”, please confirm.
⸻
5. Age-banded mortality
For each year 2015–2025, please provide age-banded mortality counts for the following groups:
• 0–14
• 15–44
• 45–64
• 65–74
• 75–84
• 85+
If different bands are used internally, please provide the closest equivalent.
⸻
6. Excess mortality by age, ethnicity, and region
If available, for each year 2015–2025:
6.1 Excess deaths by age band
6.2 Excess deaths by ethnicity (Māori, Pacific Peoples, European/Other, Asian)
6.3 Excess deaths by region/DHB area
6.4 Any internal analysis comparing excess deaths before 2020 vs after 2020 (if produced)
If no analysis exists, please confirm.
⸻
7. Internal technical papers or briefings (2020–2025)
Please provide:
7.1 A list of all internal reports, memos, technical papers, or briefing documents produced between 1 Jan 2020 and today that relate to:
• Excess mortality
• Cause-of-death trends
• Delay in death registration processing
• Changes in disease-specific mortality
• Data quality issues in mortality series
7.2 For the first five documents in each category, please provide the full text.
If full release would trigger s18(f), the list alone is sufficient for this part.
⸻
8. Format
I request all numerical datasets in CSV or Excel where possible.
Documents may be provided in PDF.
No personally identifiable information is requested.
Kind regards,
Spencer Jones
(via FYI.org.nz)
From: Office of the GS&CE-External
Statistics New Zealand
Tēnā koe Spencer
I am writing to acknowledge receipt of your below Official Information Act
request dated 19 November 2025.
We will endeavour to respond to your request as soon as reasonably
practicable and in any event no later than 17 December 2025, being 20
working days after the day on which your request was received. If we are
unable to respond to your request by then, we will notify you of an
extension of that timeframe.
Your request is being handled by the Office of the Government Statistician
and Chief Executive. If you have any queries, please feel free to contact
me using this email address. If additional factors come to light which are
relevant to your request, please do not hesitate to contact us so that
these can be taken into account.
Ngā mihi
Lily Reid (she/her)
Advisor – Executive and Government Relations, Office of the Chief
Executive
Kaitohutohu – Ngā Hononga Whakawaho, Kāwanatanga hoki, Tari o te Tumu
Whakahaere
Stats NZ | Tatauranga Aotearoa | stats.govt.nz
About Aotearoa, for Aotearoa
Data that improves lives today and for generations to come
Facebook | Twitter | LinkedIn
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From: Office of the GS&CE-External
Statistics New Zealand
Tēnā koe Spencer
I refer to your official information request dated 19 November 2025 for
excess mortality and cause-specific death statistics.
We have transferred the below parts of your request to Health NZ – Te
Whatu Ora. Part of the information to which your request relates is
believed to be more closely connected with the functions of Health NZ – Te
Whatu Ora. In these circumstances, we are required by section 14 of the
Official Information Act to transfer your request.
3. Cause-of-death by ICD-10 category (2015–2024)
For each year:
3.1 The total number of deaths for each ICD-10 “Chapter” category,
including but not limited to:
• Neoplasms (C00–D48)
• Circulatory system diseases (I00–I99)
• Respiratory diseases (J00–J99)
• Endocrine/metabolic (E00–E90)
• Nervous system (G00–G99)
• External causes (V01–Y98)
• Mental and behavioural disorders
• Infectious and parasitic diseases
• Ill-defined causes / symptoms / unknown causes
3.2 Mortality rates (crude or age-standardised)
3.3 A copy of any annual or quarterly “cause of death” statistical tables
held by Stats NZ that may not be publicly displayed on the website.
4. Specific categories of public concern
For each year 2015–2025, please provide:
4.1 Total deaths classified as:
• Sudden cardiac death
• Acute myocardial infarction
• Stroke / cerebrovascular accident
• Pulmonary embolism
• Myocarditis
• Pericarditis
• Aneurysm or aortic dissection
• “Ill-defined or unknown causes” category (R00–R99)
4.2 Total deaths coded under the following cancer subcategories:
• Acute leukaemias
• Lymphomas
• Metastatic cancers with <3 months between diagnosis and
death (if recorded)
• Pancreatic cancer
• Brain/CNS cancers
If Stats NZ does not hold the “diagnosis-to-death interval”, please
confirm.
7. Internal technical papers or briefings (2020–2025)
Please provide:
7.1 A list of all internal reports, memos, technical papers, or briefing
documents produced between 1 Jan 2020 and today that relate to:
• Excess mortality
• Cause-of-death trends
• Delay in death registration processing
• Changes in disease-specific mortality
• Data quality issues in mortality series
7.2 For the first five documents in each category, please provide the full
text.
If full release would trigger s18(f), the list alone is sufficient for
this part.
You will hear further from Health NZ – Te Whatu Ora concerning these parts
of your request.
Ngā mihi,
Sam
Sam Newbold (pronouns: he/him/his)
Senior Advisor – Executive and Government Relations, Office of the
Government Statistician and Chief Executive | Kaitohutohu Matua, Tari o Te
Tumu Whakahaere
Stats NZ | Tatauranga Aotearoa | [1]stats.govt.nz |
About Aotearoa, for Aotearoa
Data that improves lives today and for generations to come
From: Office of the GS&CE-External <[email address]>
Sent: Wednesday, 26 November 2025 3:23 pm
To: [FOI #32914 email]
Subject: Acknowledgement of your Official Information Act request: Excess
mortality and cause-specific deaths (2015-2025)
Tēnā koe Spencer
I am writing to acknowledge receipt of your below Official Information Act
request dated 19 November 2025.
We will endeavour to respond to your request as soon as reasonably
practicable and in any event no later than 17 December 2025, being 20
working days after the day on which your request was received. If we are
unable to respond to your request by then, we will notify you of an
extension of that timeframe.
Your request is being handled by the Office of the Government Statistician
and Chief Executive. If you have any queries, please feel free to contact
me using this email address. If additional factors come to light which are
relevant to your request, please do not hesitate to contact us so that
these can be taken into account.
Ngā mihi
Lily Reid (she/her)
Advisor – Executive and Government Relations, Office of the Chief
Executive
Kaitohutohu – Ngā Hononga Whakawaho, Kāwanatanga hoki, Tari o te Tumu
Whakahaere
Stats NZ | Tatauranga Aotearoa | stats.govt.nz
About Aotearoa, for Aotearoa
Data that improves lives today and for generations to come
Facebook | Twitter | LinkedIn
show quoted sections
From: hnzOIA
Tçnâ koe, Spencer
Thank you for your email of 26 November 2025 to Stats NZ. Stats NZ have
transferred parts 3, 4 and 7 to Health NZ. We will respond in due course.
Under the Official Information Act (OIA), agencies are required to respond
to requests for official information as soon as reasonably practicable and
no later than 20 working days after receiving them.
Please note that the period from 25 December 2025 to 15 January 2026
(inclusive) is not counted as working days under the OIA. As a result, any
OIA requests received on or after 29 November 2025 may take longer to
process than usual, as the maximum response timeframe may extend into the
new year.
If your request is for data that Health NZ holds, have you checked
[1]Lighthouse first to see if the data you are seeking is already
published?
Lighthouse is a searchable catalogue that makes a range of data and
analytics products available to New Zealanders to enable easier, faster
access to insights about health services.
You can find further information about how OIA timeframes are calculated,
including the Ombudsman’s OIA calculator, at the link below:
[2]Official information calculators | Ombudsman New Zealand
We will provide a response to your request in line with the statutory
timeframes set out in the OIA.
We appreciate your understanding and patience during this time.
Ngâ mihi,
Health NZ | Te Whatu Ora
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PUBLIC-FACING ANNOTATION (FOR FYI.org.nz)
Why this parallel OIA to Stats NZ matters
This OIA seeks official mortality data that is essential for understanding whether New Zealand’s excess mortality since 2020 is:
• stable,
• increasing,
• seasonal,
• age-specific,
• or linked to particular causes of death.
Many New Zealanders have noticed changes in their communities — more sudden deaths, rapid onset illnesses, and cancer diagnoses occurring at later stages. At the same time, Stats NZ publishes only high-level summaries, and some datasets are delayed by months or years.
This OIA requests:
• 10 years of mortality data (2015–2025)
• weekly deaths to identify spikes or unusual patterns
• cause-of-death numbers by ICD-10 category
• sudden or rapid-onset death categories
• age-specific and ethnicity-specific excess mortality
• internal technical papers and briefings
These datasets allow researchers, clinicians, journalists, and families to see whether lived experience matches — or differs from — what is recorded in official mortality data.
It complements the parallel OIAs on:
• health workforce exits and shortages, and
• cancer incidence, diagnostic delays, and mortality trends,
by examining the downstream impact at a population level.
Once released, this will provide one of the clearest pictures of NZ’s mortality trends over the last decade and help ensure transparency and accountability in public health data.
Link to this