50 Victoria Street
Private Bag 6995
64 4 894 5400
64 4 894 6100
9 August 2019
[FYI request #10724 email]
Dear J Bruning Request made under the Official Information Act 1982
Thank you for your email
of 12 July 2019 requesting the following information under the Official
Information Act 1982 (the Act):
1. Please can you advise which herbicides are used by NZTA across New Zealand,
including adjuvants and organosilicon surfactants (lease provide formulation names)
which are applied to roadside, highway and railway line as part of roadside management.
Please can you advise herbicides and mixtures used for each of the Upper, Central and
Lower North Island and for the South Island as climates vary and operations may differ.
2. As part of (1) please can you advise the common mixtures of herbicides, adjuvants and
organosilican surfactants (referred to as tank mixes) used in roadside, highway and
railway line applications.
3. Please can you provide details the total quantities of specific herbicides used in
managing road, highway and railway track applied annually across New Zealand.
4. Please can you provide an estimate of the approximate frequency of application of the
above herbicides applied annually. This may differ for region so please can you provide
the application frequency for the Upper, Central and Lower North Island and for the South
The NZ Transport agency is unable to provide any information relating to local roads or KiwiRail
assets because we do not hold any information on their behalf. We have provided information for
all State Highways. If you would like information on local roads, please contact the relevant road
controlling authorities (such as the relevant local council). If you would like more information on
railway tracks, please contact KiwiRail.
The following documents fall within the scope of your request and are enclosed:
• Attachment 1: OIA-5436 questions 1,2 and 4.
I am refusing question 3 of your request under section 18(e) of the Act because the information
does not exist. We do not record the information, please note that the quantity will vary
considerably depending on the seasonal variances year to year, the number of times treatment is
applied, and the area treated each time.
It’s important to note that the products used are in line with recommended good practice and in
accordance with local resource consent conditions. Any products used by our contractors must
be safe, legal and fit for purpose.
Under section 28 of the Act, you have the right to ask the Ombudsman to review my decision to
refuse this information. The contact details for the Ombudsman can be located at
If you would like to discuss this reply with the Transport Agency, please contact Rob Campbell,
Manager System Management by email to [email address].
Acting Senior Manager, System Management