"Institutional and legislative frameworks also need to move from their current focus on recovery after an event towards reducing risk before an event."
Professor Ilan Noy, Victoria University's chair in the Economics of Disasters, said councils weren't often able to deal with climate problems, because they often lacked knowledge and resources, or appeared to find it more difficult to deal with local interests.
"Central government needs to be involved much more heavily than it currently is in both providing resources and guidance to local government, and in sometimes assisting it in making difficult choices."
The recommendations have been welcomed by councils' lobby Local Government New Zealand (LGNZ), which has already called on Wellington for a new national adaptation fund and risk agency.
Its president, Dave Cull, said councils relied on long-term planning, so any extra funding would provide certainty around meeting climate change adaptation.
The draft report was also applauded by a leading expert in the space, Dr Judy Lawrence of Victoria University's Climate Change Research Institute.
Lawrence noted its call to align legal frameworks so councils could have more backing when making planning decisions that addressed climate risks.
Another expert, Otago University's Professor Lisa Ellis, said that every day that passed without clarity on climate change adaptation policy brought new losses.
"We are investing in risky coastal development without knowing who will protect those investments or how they will be protected; we are making decisions about existing assets without knowing our real options; in the face of increasingly frequent and extreme natural hazards, we are hoping rather than planning for the future," she said.
"The Productivity Commission rightly puts helping councils adapt to climate change at the top of its list of urgent actions."
An earlier LGNZ report showed that $2.7 billion of roading, water and building infrastructure was at risk from as little half a metre rise in sea level.
The value of at risk infrastructure ramped up sharply at each increment of sea level rise, with the data showing that $5.1b worth was at risk at 1 metre of sea level rise, with $7.1b at risk at 1.5m and $14.1b at risk at 3m.
Under present projections, the sea level around New Zealand is expected to rise between 30cm and 100cm this century.
