"Assessors have been mobilised, but we would like to remind our customers to be aware of the potential issue of contaminated, or 'black' water, which can pose a health risk.
"It is a common issue during cleaning up after a flood event, therefore we have developed guidelines for anyone who has concerns or is experiencing this problem at the moment. Please take extra care while you are dealing with potentially contaminated items," Olsen said.
People should wash cooking, eating and other kitchen utensils that had been covered by the water, the insurer said. Flood water can also make air inside a house unhealthy.
"When things get wet for more than two days, they usually get mouldy. There may also be germs and bugs in your home after a flood. Mould may be more likely to make some people with asthma, allergies and other breathing problems sick."
The warning said people should not enter flooded premises before officials had said it was safe. Buildings could have hidden damage making them unsafe and people should look for electrical damage and beware if they see sparks or broken or frayed wires.
Vero said yesterday it had already received 200 claims worth about $700,000 but those were likely to rise.
AA Insurance said it had handled almost 560 flood-related claims during the weekend, mainly from people living in low-lying areas.
Read the full IAG warning here: