Malcolm Turnbull and Bill Shorten have urged insurers to support storm-hit communities as they agreed on a package of support for victims.
The storms and flooding which hit over the weekend have left four people dead and three missing in NSW, the ACT and Tasmania.
By 9am on Tuesday, 14,500 people in Queensland, NSW, Victoria and Tasmania had lodged insurance claims with estimated insured losses of $56 million.
But many Sydney beachside residents are being told they are not covered by "actions of the sea" and may need to resort to government payments.
Mr Turnbull, who visited Picton southwest of Sydney on Tuesday with NSW Premier Mike Baird, said he was sure insurers would support the hardest-hit communities.
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"This is very substantial storm damage," he said.
Mr Shorten, who visited Coogee on Tuesday afternoon, urged insurers to treat customers fairly.
"Make sure you deal with their claims in a speedy fashion," he said.
"For people who have suffered significant damage, the last thing they need is to be damaged again by a long argument with an insurance company."
An insurance catastrophe area was expanded on Tuesday to cover the east coast of Victoria and Tasmania's northern and eastern coastlines.
As the federal government is in caretaker mode, Mr Turnbull consulted with Mr Shorten on an open-ended support package for families and businesses affected by the flooding and storms.
The package includes interest-free loans and grants for individuals, small businesses and community groups of up to $130,000.
"We are absolutely united in thanking and supporting the communities that have been affected by these shocking storms," Mr Turnbull said.
The opposition leader said it was a moment to support people in trouble.
"In the worst of times, we see the best of Australia."
Mr Shorten said he was particularly concerned about Tasmania, which was likely to see more flooding.
"We don't want to see any more people lost to this terrible weather ... if the SES give you advice please follow it."
