Sydney's coastal homeowners face their property values being reduced, as the future risk of increasingly extreme weather events grows, a climate risk consultant says.

Dr Karl Mallon, director of science and systems for Sydney-based consultants Climate Risk, said Australia's quintessential problem is that "you can build a house which is insurable tomorrow, but is wholly unsuitable 30 years down the track".

The message follows the release by the independent Climate Council of its latest report, Super-charged storms in Australia, which argues that the nation is highly vulnerable to "storm surges associated with tropical cyclones and extra-tropical cyclones, including [more intense] east coast lows."

"The evidence for the link between climate change and extreme weather is already very strong for heatwaves and bushfire weather, and it is getting stronger for intense cyclones and heavy rainfall events," the report said.

"Seven storms since 2010 in Australia have resulted in insured losses of more than $500 million each, and five of them resulted in over $1 billion in insured losses."

Dr Mallon said that many Australians do not realise that a change in a property's value does not occur when an extreme weather event takes place, but "when the market realises the event will occur and revalues the house...it's the homeowner which is the sitting duck in all this."

He pointed to a "disconnect," between banks, government planning and the insurance industry, which is leaving Australian homeowners vulnerable to "climate change foreclosure".

"There are potentially millions and millions of dollars of revaluation that has to happen in the property sector and it's not going to be pretty. We could end up with suburbs where there is a wholesale collapse in value," he said, highlighting "erosion, actions of the sea, landslip and ground contraction," as some of the main impacts which are still largely uninsurable.

"It's the banks who probably need to lead the charge…to sit down with insurers and planners and say, 'Will you start providing insurance on this?'."

Storm damage, hail and flooding caused 70 per cent of all insurance losses in NSW between 1970 and 2013, a report by insurance giant IAG and consultancy firm SGS Economics and Planning showed last week. That report identified Hawkesbury as the most disaster-prone region of greater Sydney, ranking among the city's highest risk council areas for flood, storm and bushfire. It was among 10 council areas identified as having a "high" or "very high" risk of major flooding, including Camden, Fairfield, Rockdale and Woollahra.

At the start of next year, Climate Risk will launch an online valuation tool, in which users can type in an address and run an analysis on how climate change could impact on the property's value in future.

The system recalculates the value of a property at the end of a mortgage, by analysing climate and coastal data; such as tide, tectonic and wave gauges.

"We are not building with climate change in mind....we need someone to start talking about the risks going forward. So we've been building these products to be able to do that."

This week the Insurance Council of Australia launched a national campaign, urging Australian home and business owners to prepare for a potentially severe disaster season.

A sewerage pipe is exposed in storms at South Narrabeen. Photo: Peter Braig

"An above-average cyclone season has been forecast by the weather bureau, while the Bushfire and Natural Hazards Cooperative Research Centre predicts heightened risk across much of southern Australia, especially in New South Wales, Victoria and Western Australia," said ICA chief executive officer Rob Whelan.

Campbell Fuller, the Insurance Council's general manager of communications, said around "95 per cent of household insurance policies purchased now include cover for flooding but consumers can also buy policies where flood cover is optional, or which exclude flood damage.

For coastal dwellers, he said there was a small number of available policies that covered damage caused by actions of the sea.

"Australian governments could do more to prepare the community and reduce the impacts through mitigation, a process sometimes held back by a lack of understanding of the risks [and] budgetary pressures," he said, adding that governments at every level needed to lift their level of mitigation spending.

"This process is accelerating, as government's understanding of the impact of natural disasters grows, although insurers continue to deal with the consequences of historical decisions."

In March, the Australian Business Roundtable for Disaster Resilience & Safer Communities revealed that the total cost of natural disasters in Australia in 2015 exceeded $9 billion, or 0.6 per cent of GDP, a figure expected to double by 2030 and reach an average of $33 billion by 2050.

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