The average annual cost to repair homes damaged by river floods is more than $100 million and forecast to rise, according to new analysis.
The flooded Maitai River flows past a house in Nelson on Thursday. Photo: RNZ / Angus Dreaver
A joint report by property research firm CoreLogic and reinsurance provider Munich Re indicates the annual repair build could rise more than 20 percent by 2050, and in excess of 30 percent by the turn of the century.
Munich Re Australia managing director Scott Hawkins said in a statement New Zealand could expect to see an increase in both the frequency and severity of weather events due to climate change.
"Weather-related disasters might in sum become as destructive to New Zealand as earthquakes," Hawkins said.
"As the risk increases strongly for many regions, it is essential for communities, commercials and individuals to understand and manage their exposure to climate risks."
This bridge on the main highway through Tokomaru Bay on the East Coast was badly damaged in flooding in March. Photo: RNZ / Tom Kitchin
The analysis found 11 percent of the 1.6 million residential properties in New Zealand were exposed to river flooding and that could rise to 17 percent in the next 30 years.
Of the current properties exposed to river flooding, 5 percent were within 100-year flood risk zones, but were expected to rise to 9 percent by 2050.
CoreLogic head of research Nick Goodall told RNZ some parts of the country could be too expensive, with unaffordable insurance, if insurers were even still willing to offer cover.
He said that was already happening in places, with some property owners paying risk-based premiums.
"This [analysis] just shows that it's going to keep increasing as we see more of these events and more properties that are exposed."
Goodall said people should assess the risks they face given the location of their property and should consider moving to a place where they might be less exposed to those risks, or prepare to pay higher premiums.
He said investing in mitigation, such as flood walls, was a short-term measure, and could encourage people to live in risky areas.
Otago was identified as having one of the highest flood risks in the country.
"Otago accounts for 5 percent of total national residential property value, but 15 percent of the national annual average river flood loss," the report said.
Hawke's Bay, Manawatū-Whanganui and Marlborough would also see some of the highest increases in rebuild costs by 2050, as river floods became more frequent.
Auckland and Wellington were exposed as well, the report said.