The researcher, who is advising the government on how New Zealand should share the costs of adapting to climate change, also said some house prices in the area were unreasonably high, and further, that parts of the suburb had "a time limit on them".
Climate Sigma managing director Belinda Storey, speaking to the Otago Daily Times in a personal capacity yesterday, said the flooding that prompted calls for evacuations in South Dunedin last week was "understandably distressing" for the people involved.
"But it’s not surprising," Ms Storey said.
"These events are going to occur and will occur with more frequency as our climate changes.
"And so, particularly those properties that are most low-lying can expect to see this type of flooding repeat."
In 2015, a significant downpour overwhelmed an ill-equipped Three Waters network in the low-lying suburb.
This time, nine years later, relentless rain was more than the upgraded, now well-functioning network could handle.
And so again South Dunedin streets and homes filled with water.
The Insurance Council of New Zealand yesterday said across New Zealand there were places "affected by weather events over a period of time" and insurance continued to be generally available.
"This also applies to Dunedin."
However, Ms Storey said there would be insurers already considering walking away from some South Dunedin properties.
The area was very flat and yet there were some locations within it that were even lower where the water collected first.
"So even if you’re a one-in-100 [year flood zone], there will be properties that are effectively in a one-in-50, or a one-in-20 [year flood zone], just because they’re the lowest-lying properties inside that flood zone.
"Those are the houses that are going to experience the flooding most frequently."
It was possible that houses might receive a claim for this particular event, and get insurance for the following year, but in the second or third year "they might find it difficult to get their policy renewed".
At the moment insurers were choosing to cross-subsidise across entire suburbs.
"But when houses get hit repeatedly, insurers are going to make decisions about whether they want to continue to offer insurance."
It was more likely that insurers would walk away "as quietly as possible" than hike premiums significantly, which was much more visible, she said.
"It has a more direct reputational damage on the insurer if someone says ‘my insurance premiums have gone up by 500%’, than if an insurer simply says, ‘We’re not going to continue to insure you. We’re declining your policy this year’.
"It’s a quieter way for the insurer to manage the risk."
Ms Storey also said yesterday she believed within South Dunedin "there are some locations that have got a time limit on them".
"And we need to do everything we can to make sure that the market starts to recognise that.
"Following the 2015 floods, the property prices fell and then they bounced right back in.
"That’s not a reasonable reflection of the risk and the fact that there are parts of South Dunedin that we’re not going to be able to sustain in 100 years’ time.
"I think we need to be undertaking measures to ensure that the market much better reflects that risk and reflects the fact that these properties have a time limit on them."
A spokesman for the Insurance Council said insurers had a "long and ongoing awareness" of low-lying areas such as South Dunedin, and concerns about rising groundwater and sea level rise.
They were continually evaluating these types of risks around the country, including any mitigation and adaptation measures that had been taken by councils such as the Dunedin City Council to reduce the impact of climate change, he said.
"The impact of extreme weather events that we have experienced in the last couple of years on lives and property has brought the issue of resilience into sharper focus.
"We have consistently said it’s important New Zealand takes a long-term view on the risks from natural hazards as we face the prospect of more frequent and severe events due to climate change.
"We support a cross-party political consensus to tackle the urgent challenges of climate change that brings together central government, councils, the private sector and communities to effectively mitigate risks and ensure insurance is affordable and accessible."
In terms of future insurability, the spokesman said insurers would review insurance levels at renewal and take into account "a range of factors" when assessing risk such as the age of the property, how well it was maintained, claims data, their own modelling and information from councils and natural hazard modelling companies.
The most common measure taken by insurers was premium loadings or increased excesses for particular hazards, the spokesman said.
"Far less common is excluding a natural hazard or declining cover all together."
The Insurance Council did not yet have exact figures for the number of claims across Dunedin related to last week’s storm, but early indications were that it was likely to be in the low hundreds, he said.
South Dunedin Future was approached for comment yesterday, but could not respond immediately.
