The catastrophic floods that swept through southeast Queensland and northern NSW earlier this year now constitute the third costliest extreme weather event in Australia's history.
New Insurance Council of Australia data shows the unprecedented rain that caused widespread devastation in late February and early March caused $4.8 billion in insured damages.
The disaster now ranks only behind Cyclone Tracy in 1974 and the Sydney hailstorm of 1999.
"The sheer scale of the extreme weather event that devastated Queensland and NSW is something we have never seen before, and the cost continues to rise," ICA CEO Andrew Hall said on Tuesday.
"Money is flowing into these devastated communities with $1.5 billion already paid and this number increasing every day."
Nearly 225,000 insurance claims have been lodged across both states, an increase of 3.6 per cent on last month.
Insurance costs for the event have increased 12 per cent on last month, driven in part by increasing materials and labour costs.
Almost 30 per cent of claims have been closed, with $1.5 billion paid to policyholders, with almost 125,000 home claims stemming from the floods.
Mr Hall said local councils needed to prepare for an influx of development applications for a large number of property rebuilds and repairs.
"Councils need to be looking at what they can do to process the higher than usual number of development applications we expect to see as a result of this flood," he said.
This week marked four months since the ICA declared the floods a catastrophe.
The event stretched over several days and many claims were not made until days, weeks or months after the initial event, with locations like Lismore in Northern NSW being hit for a second time at the end of March, generating many new or additional claim lodgements.
The four-month mark is significant because insurers are required to make a decision on a claim four months after it is lodged.
However, the code allows for changes to timeframes where they cannot be practically met, for example, due to the complexity of the claim or delays in expert reports, such as hydrology and engineer reports.
The ICA has been holding community forums in impacted towns and cities throughout June, which has enabled insurance customers to meet directly with their insurers.
