Families and firms in Northern Ireland who make claims connected to flood damage sustained in recent days could have difficulty finding future insurers or face massive hikes in premiums.
The warning comes as insurance companies gear up to pay out millions of pounds after this week's torrential rain. Industry experts said those lodging a claim for damage to their homes, farms and businesses were likely to get a payout, but they warned that firms could decline to provide them with flood cover in the future or impose a hefty excess on claims.
Paul Hatty, of J Hatty and Co insurance agency, said homeowners and members of the business community could struggle to find an insurer.
"When someone has had a claim for flooding and is in a known flooding area then it can be hard to get insurance," he said. "Insurers don't want to take a risk on something that is inevitable. They want to deal in unforeseen incidents."
To date 20 families have been rehoused in emergency accommodation after floods in the north west destroyed their homes, while more than 100 people were rescued from cars and houses in counties Tyrone, Londonderry and Donegal after 63% of August's average rainfall fell in nine hours.
Roads and bridges crumbled, cars were washed away and homes and businesses were destroyed in storms that hit the area with a vengeance on Wednesday.
Alliance MLA Trevor Lunn, who ran an insurance brokerage for 25 years, said insurers will pay for damage sustained in the recent deluge but may think twice about providing future flood cover.
"Insurance companies cover the unexpected," he said.
"They may refuse to cover homes and properties in certain areas if there's a liability of flood damage and no remedial action has been taken, or they can impose a substantial excess on water damage claims.
"Households could also get insurance to cover the cost of rebuilding and contents, but insurers could put in exclusions so that they wouldn't have to pay out on flood damage."
He added: "But it's up to the individual insurer. If you've been a customer for 20 years and you've claimed once because six centimetres of freak rain fell in one night, then it's likely they will reinsure."
The Northern Ireland Housing Executive (NIHE) said 26 of its properties in the Londonderry area were badly damaged resulting in vulnerable, young and older people having to be rehoused.
Fears are rising that claimants could be left high and dry once damages money is paid out because of reports that some firms will blacklist areas that had previously experienced flooding.
Paul Kavanagh, who heads up McCarthy Insurance Group, one of the largest brokerage companies in Ireland, which also experienced horrendous floods, said this was the case even where flood relief works had been carried out.
"The insurance companies won't admit it, but when flooding happens you are blacklisted," he said. "They won't provide you with flood cover."
But Malcolm Tarling from the Association of British Insurers (ABI) insisted that the "number one priority is to deal with the current claims as soon as possible" to get people back into their homes.
"Just because you've had one flood claim doesn't mean you won't be able to get flood insurance in future," he said.
"The cost of insurance depends on many factors. If you live in a higher risk area - such as by a river that is prone to flooding - then you might pay more anyway. Our advice is to shop around; it should be a competitive market."