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Responding to the Overseer review – advisory note

This advisory note helps regional councils to assess and respond to the Overseer Peer Review Science Advisory Panel’s report and should be read in conjunction with the Government’s Response Report.

This advisory note assists regional councils with assessing and responding to the Overseer Peer Review Science Advisory Panel’s review report (the Review Report). Importantly, this note does not constitute government direction, and should be read in conjunction with the Government’s response report (the Government’s Response).



The advisory note is a starting point for councils to consider the implications of the Review Report, and to identify options that may help them formulate their response. Individual council’s responses to the Review Report will depend on their regional context; Overseer has been used in council planning documents in various ways, and councils will need to decide how best to account for the Panel’s findings. Some of this advice may not be relevant to every council, and this advisory note does not override each council’s obligations to implement their statutory plans and resource consents in accordance with the law.

The Ministry for the Environment (the Ministry) will also continue to assist councils with their freshwater plans, consents, and compliance monitoring and enforcement (CME) requirements. As a result, this advisory note will be updated from time to time; please visit Overseer Response for the most up-to-date information.

Publication reference number: INFO 1016

General principles

The Government’s Response summarises the Review Panel’s conclusions regarding Overseer, and we have not reproduced those conclusions here, other than to acknowledge the Review Report raises concerns that must be addressed.

The Government’s Response acknowledges that councils need a range of tools to achieve freshwater outcomes, and the Government has committed to ensuring regional councils and resource users have access to reliable and practical tools to effectively manage nutrient discharges through the planning and consenting framework. The aim is to have fit-for-purpose tools available for use within 12 months.

In the meantime, at the broadest level, the Ministry recognises that councils must continue to implement their plans, administer existing consents, and process new consent applications in a manner that promotes the objectives and policies of their respective plans and the National Environmental Standard for Freshwater (NES-F), despite the issues raised in the Review Report. We suggest that councils are alert to the Panel’s concerns about Overseer and where possible within their existing policy and consenting frameworks, adopt a best information approach and look for opportunities to support decisions made using Overseer data with multiple lines of evidence. Furthermore, issuing new consents and preparing new plans or changing existing plans to allow for the future use of new or redeveloped tools will provide for maximum future flexibility when those tools become available.

Publication reference number: INFO 1016

Proposed plans and plan reviews in process

The Ministry recognises that councils have plans at varying stages of development; the effect of the Review Report on these plans will therefore vary depending on the extent to which a plan uses Overseer as a nutrient management tool.

Current plan hearings and appeals

Councils can continue with existing plan processes but are encouraged to take account of the findings in the Review Report where there are opportunities to do so in the planning process. Where possible, councils may wish to consider opportunities through the RMA Schedule 1 process to complement the use of Overseer as a nutrient management tool. As highlighted in the Government’s Response, this will be particularly important where landscape factors and other evidence suggest nitrate-nitrogen is not the dominant species of nitrogen loss at the farm or catchment scale.

Importantly, any alternative approaches to Overseer-based limits on resource use will need to give effect to the National Policy Statement for Freshwater Management 2020 (NPS-FM). Plan changes that give effect to the NPS-FM must be notified by 31 December 2024 (section 80A of the Resource Management Act 1991 [RMA]).

Plan development

A key impact for regional councils will be the ability to set nutrient concentrations and exceedance criteria (NPS-FM clause 3.12) and translate these into limits on resource use (including property-scale controls). Refer to the Ministry’s recent guidance for setting instream nutrient concentrations.

Overseer can still be used to develop catchment loads or limits (subject to the qualifications set out in section 4.2.1 of the Government’s Response), so preparations for publicly notifying new freshwater planning instruments to achieve target attribute states can continue.

Publication reference number: INFO 1016

Operative regional plans that use Overseer

Regional councils are legally obliged to continue to implement their plans, administer existing consents and process new consents in a manner that promotes the objectives and policies of their plans. The Review Report does not change this. Where operative plans use Overseer, considering other information in addition to Overseer, where possible, may give increased confidence in councils’ nutrient-management decisions. More information about implementing operative plans is provided in the Consents and Compliance monitoring and enforcement sections.

Publication reference number: INFO 1016

Overseer and compliance monitoring and enforcement

Existing resource consents and permitted activity rules remain valid authorisations of resource use. Councils can continue to monitor these authorisations to establish the level of compliance that is occurring with the relevant national and regional policy, and their plans.

Prioritising high-risk activities

Most councils already prioritise their compliance monitoring and enforcement (CME) work to those activities that pose the greatest risk to national and regional policy objectives. Councils may wish to check that their monitoring system appropriately prioritises compliance monitoring of resource consents that relate to nutrient loss, where they are considered at greater risk of non-compliance and are associated with higher potential for adverse environmental effects. Higher risk consents may include resource consents that:

  • include a nutrient leaching limit, where an Overseer assessment is required for compliance
  • require reductions in permissible nitrogen leaching
  • manage multiple properties or complex farming systems (such as irrigation schemes).

For these types of consents, councils may wish to consider increased monitoring and working directly with consent holders to maximise opportunities for compliance, and ensure they are well informed of the Review Report’s findings on the Overseer model.

Should it become apparent that changes are required to the resource consent to ensure potential adverse effects are appropriately avoided, remedied or mitigated, the council may wish to consider reviewing the consent under section 128 of the RMA. It is possible that in some situations, a consent holder may apply to change consent conditions under section 127 of the RMA (other than in relation to consent duration). Councils should continue to exercise their usual decision-making when considering these options.

Managing the risks of increasing nitrogen discharges

There is a risk that some resource users may perceive the Review Report as an opportunity to increase farming intensity before new or improved tools are available. It is important that land use is not able to intensify because of the Review Report findings, in order to maintain the direction of travel for delivering on the Essential Freshwater programme.

The intensification controls within the NES-F will help to mitigate the risks of land-use change and excessive fertiliser use. When councils are setting conditions for new resource consents, using targeted input-based or practice-based controls (where this is possible under the operative plan), as well as any required use of Overseer, may also provide some protection against this risk.

Councils are encouraged to think broadly about regulatory requirements in their existing plans and resource consents that may help mitigate the risk of uncontrolled intensification, and to consider whether there are steps beyond existing CME activities that could further mitigate this risk.

The Government will monitor this intensification risk closely and may consider amending national instruments if uncontrolled intensification becomes apparent.

Publication reference number: INFO 1016

The next 12 months

Further details of the Government’s programme for the next 12 months can be found on the Overseer Response page.

The Ministry is committed to supporting councils as they manage the implications of the Review Report. This support may be collective or individual to each council, depending on their specific needs, and the Ministry will continue to work with councils to determine what support is most useful and appropriate. Please email us if you require further support.

Publication reference number: INFO 1016