INSURANCE claims are likely to exceed $1 billion this summer after heavy rain lashed large parts of NSW on the weekend, adding billions of litres of water to already swollen rivers.
The Bureau of Meteorology issued a severe thunderstorm warning with a risk of flash flooding on Sunday for residents of the Hunter, south coast, northern tablelands and parts of the northern rivers.
It came less than 24 hours after severe winds and rain hit hundreds of homes across Sydney and the Illawarra, leaving towns across eastern NSW battling rising floodwaters.
More than a dozen major or minor flood warnings were issued on Sunday after heavy rain dumped an average of 94 millimetres over the Warragamba catchment in 24 hours.
The latest figures from the insurance industry show claims for NSW, Queensland and Tasmania have jumped $150 million in the past two weeks, pushing the total value of insurance claims this summer above $830 million.
Figures from the Insurance Council of Australia show losses in Queensland have climbed to $661.3 million this year, followed by flood-related losses in NSW of $71.8 million. Tasmanian bushfire claims have risen to $87.1 million, while claims related to bushfires in NSW total $10 million.
Insurers said they were expecting the total value of losses to grow in coming weeks but it was too early to know how many fresh claims will be made after this weekend.
"It's not unusual for [claims] figures to balloon more than a week after [an] actual event," said Campbell Fuller, a spokesman for the Insurance Council. "We're not due to get some more figures until the end of this week."
The severe weather comes as QBE Insurance prepares to publish full-year earnings this week.
Last week, two of the country's biggest insurers - Suncorp and Insurance Australia Group - posted huge jumps in six-month profits.
Suncorp's net profit jumped by close to half, to $574 million, while IAG's profits more than tripled to $461 million.
Insurance analysts said IAG's profit margin, which jumped in the past year from 7.7 per cent to 19.2 per cent, was the best in living memory.
In the same week, IAG, the group behind the NRMA, RACV and CGU insurance brands and the country's biggest insurer of cars and homes, said its home and car premiums could rise by 5 per cent to 10 per cent this year.
For the six months to December 31, the group paid out $133 million on claims.
However, this calendar year, it has so far spent $120 million to $140 million on flood-related claims and $35 million on the bushfire-related claims.