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.
In this section
Find out more our assurance function and about the Investment Decision Assurance process.
Review guidance and workbooks
Find out about the key review criteria and download detailed workbooks on each Point Review.
About Investment Decision Assurance
Investment Decision Assurance is about providing independent assurance to ministers on high-risk central government investment decisions while helping Senior Responsible Owners identify and address delivery risks as projects develop
Frequently asked questions
Answers to commonly asked questions about the Investment Decision Assurance process. Questions will be added to this page over time.
Need to request a review?
Agencies need to request a review at least 4 weeks before the review starts. This allows time to confirm the review arrangements and provide the required information.
If you are at the stage where you need to book a review, please get in touch with our Investment Decision Assurance (IDA) team to book.
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 are 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.
