Assurance

New Zealand spends a lot on infrastructure, but we’re not always getting value from this investment. A strong assurance system makes sure that decision-makers have the information they need to make well-informed decisions on investments.

Investment Management System changes

The Treasury is kaitiaki of the Investment Management System, providing stewardship and leadership through three functions – investment management policy, investment reporting, investment reviews.

In April 2026, the New Zealand Government agreed to five changes to the Investment Management System with the aim of strengthening investor assurance to focus on what Ministers need to make good well-informed decisions. One of the changes was to develop a new assurance review process called Investment Decision Assurance (IDA). The new IDA system replaces Gateway reviews, delivered by the Treasury, and our Infrastructure Priorities Programme. The Treasury is responsible for the new IDA policy.

In most cases, IDA reviews are required for investments that are: 

• delivered by government departments or Crown Entities
• funded by central government

• rated as high-risk by Treasury through their Risk Profile Assessment

Assurance reviews will be based on one of two frameworks: 

• Infrastructure Assurance Framework for infrastructure projects, delivered by Te Waihanga 

• Digital, Equipment and Change Assurance Framework for non-infrastructure projects (including data and digital, organisational transformation, and specialist equipment) delivered by the Treasury. 

The IDA policy and frameworks are to be considered by Cabinet and Ministers in October 2026 with IDA reviews planned to go live from Monday 2 November. Until we have final approval, the IDA review process is subject to change, however the document below outlines the proposed process.

IDA overview of proposed review process 

Further information will be available here once the policy and frameworks are approved by Ministers.

Guidance for government agencies

If you work in a government agency that is likely to require an IDA review for your infrastructure project, we have a number of opportunities over the coming months to help you and your team learn about the new review process, what to expect and how best to prepare.

 All dates below are still to be confirmed while we wait for the Cabinet and Ministerial approvals, but here’s what we’re planning: 

Webinars

• Introduction to Investment Decision Assurance, Tuesday 13 October 2026
• Investment Decision Assurance review process, Tuesday 20 October 2026 
• Overview of Point 1-3 reviews, date to be confirmed

Ask us anything

• Monthly online drop-in sessions, week commencing Tuesday 27 October 2026

Have specific questions about the new process?

• Our team is available for individual agency meetings from 21 October 2026
• We will prioritise agencies who have reviews from November through Q1 2027 

Get in touch with us to register for upcoming webinars, Q&A sessions or speak to us about having an individual agency meeting. You can get in touch at IDA@tewaihanga.govt.nz