New Zealand still hasn't fixed the policy problems that slowed Christchurch's rebuild and remains under-prepared for another big quake, a think tank report has found.

The report from the New Zealand Initiative says the city's recovery was "substantially hindered" by avoidable mistakes in policy but that the lesson has still not be learnt.

"The government was right to implement a recovery agency like CERA, but its governance arrangements were rushed and became increasingly problematic as the scope of its activities increased," author Bryce Wilkinson said.

The study calls for the establishment of an "off-the-shelf framework" for recovery agencies, putting disaster contingencies into council's long-term plans and progressing changes to Earthquake Commission coverage trialled in Kaikoura.

"Such changes would help reduce the problems Christchurch experienced. Otherwise recovery from the next disaster will be unnecessarily difficult and costly," Dr Wilkinson said.

"The overarching lesson of the Christchurch earthquakes is that policy and regulatory uncertainty is terrible for recovery.

"Homeowners and business owners need to know quickly what the rules are for rebuilding their homes, lives and businesses."

The report also highlights the need to focus on Wellington.

"Wellington is our home, the seat of government, and most at risk for the next earthquake," NZ Initiative executive director Oliver Hartwich said.

"We need to work now to make sure that, when the time comes, recovery is as smooth as possible."

The report was launched on Thursday with a foreword by Christchurch mayor Lianne Dalziel.