Councils need to strengthen flood protection planning

Councils need reliable information, clear plans, and effective community engagement to protect people and property from increasing flood risks, says the Auditor-General in a new report.

Flooding is New Zealand's most frequent natural hazard, and climate change is increasing the threat. Recent events show how livelihoods, property, and essential services can be disrupted or destroyed by flooding.

"Appropriate planning, investment, and monitoring can reduce the impact of flooding," says the Auditor-General Grant Taylor. "Communities need confidence that council flood defences are in the right places, built to the right standards, and properly maintained."

More than 20 councils are responsible for building and maintaining flood protection infrastructure. It is a vital line of defence, but councils face difficult choices about where to invest, and how to manage increasing flood risks.

The Office's work looked at how two councils, Tasman District Council and Waikato Regional Council, mitigate flood risks from rivers and inland bodies of water. Our work also provides other councils with observations on how they can improve their flood protection planning.

We found that both councils need better information about flood risks and their flood protection infrastructure to make well-informed decisions. With councils facing significant cost pressures, the report also recognises the difficult trade‑offs involved in funding flood protection.

"Councils cannot afford to protect every area from all potential flooding. But accurate information and well-informed planning can make a significant difference," says the Auditor-General.

As councils consider their future flood protection needs, they will also need to engage well with their communities with clear information about flood risks, the options for reducing them, the costs and benefits, and the level of flood risk that remains.

"Accurate information, clear priorities, and open conversations with their communities will help all councils make sound and transparent decisions and plan effectively for future floods," Mr Taylor says.

The Auditor‑General's recommendations will help all councils strengthen their flood protection planning. The Office will focus on this area as part of its next review of council long‑term plans in 2027.

Read our full report and recommendations here: https://www.oag.parliament.nz/2025/flood-protection