Beyond the Bridge Riwaka co-ordinator Melissa Girvin, with Riwaka home owners Jamie and George Milne at their home that they have only just moved back into after ex-tropical cyclone Gita swept through the area in February.

Scientists have estimated the costs of climate change for 10 years in New Zealand, and say it will increase.

Studying adverse weather events from 2007-2017, NIWA found that climate change-related to floods and droughts have cost the New Zealand economy at least $120 million for privately-insured damages from floods and $720m for economic losses from droughts over the last 10 years.

However, that was said to be a conservative estimate.

Riwaka resident Jamie Milne said after Cyclone Gita, drainage remedies cost her $26,000, and repairs to her house were $52,000.

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MARTIN DE RUYTER/STUFF Many homes were inundated during cyclones Fehi and Gita.

Knowing more about climate change could help regions to plan for future events, she said.

"Maybe this could help the infrastructure of the areas, in this particular area anyway.

"[The flood] came through our back fence, from a river bursting its bank."

In the Riwaka area, she said drainage could be looked at.

ROSA WOODS/STUFF Makara Beach residents were cleaning for weeks after cyclone Gita. Pictured are old foundations, which the cyclone unearthed.

There could also be consideration given to the remnants of felled trees, which were potentially blocking rivers, she said.

NIWA climate scientist Dr Daithi Stone said the report was different to past estimates, because it examined extreme weather events which actually occurred.

"It identifies specific types of weather events which we expect to occur more frequently in the future and which already cause costly damage.

"If we can make ourselves less vulnerable to these types of weather events we will have cut the future costs of climate change substantially."

The study didn't attempt to analyse trends but compared the recent 10-year-period with a hypothetical world where the climate was as it would have been without man-made emissions.

NIWA climate scientist Dr Trevor Carey-Smith said climate change costs were increasing.

"The rate of this increase will depend on what mitigation strategies are enacted and how quickly emissions can be reduced."

NIWA principal scientist of coastal and estuarine physical processess Dr Rob Bell said knowing the rising costs could help planning to reduce the rising risk.

It could improve the future resilience of services and infrastructure like bridges, river stopbanks, and stormwater, Bell said.

The report says the study probably underestimated the full economic costs, as it ignored loss in economic activity in the aftermath of the events.

Forest & Bird climate advocate Adelia Hallett said climate change put industries and workers at risk.

"Jobs are already being affected by climate change. Just last week the fishing industry announced it would have to voluntarily reduce the amount of hoki it catches off the West Coast ... warming water means the fish just aren't there."

Forest & Bird wants workers to be part of the zero-carbon future conversation.

Wellington City Council programme manager for climate adaption Jacqui Hastie said during Cyclone Gita Makara Beach had the greatest concentration of damage in Wellington.

"We will need to understand the costs and benefits of the options, including the cost (and benefits) of not doing anything."