It's too early to tell what the clean-up costs from the current flood crisis will be, Treasurer Josh Frydenberg says.
But if the 2011 floods in Queensland are anything to go by, the economic impact could be in the billions.
The treasurer said following those floods, there was $2 billion in insurance claims and more than $4 billion in economic impacts across sectors such as agriculture, mining and tourism.
"Every disaster is different so I wouldn't want to put a figure on it, but already 47,000 insurance claims have been lodged," he told reporters in Canberra on Wednesday.
"It is unclear as to what the precise economic impact will be, but there will clearly be a big clean-up bill."
Mr Frydenberg said the majority of insurance claims so far have been made in Queensland with more expected to come through from NSW.
Nearly 150,000 disaster support payment claims have already been requested in Queensland and northern NSW, as heavy rain heads south.
Government Services Minister Linda Reynolds said there have been 145,000 claims for government support so far, 90,000 of which were filed on Tuesday.
The emergency federal support is a one-off payment of $1000 for adults and $400 for children affected by floodwaters.
Senator Reynolds said the number of claims is "of a magnitude beyond" anything the government has seen before in a flooding event.
But she would not be drawn on whether the payment, which has been at the same rate since 2006, should increase.
"At the moment, that's what it is," she told ABC Radio National.
"This is a payment for people who need to buy food and emergency supplies ... it is a payment for people to get through the next few days."
The minister confirmed 35,000 people have already received the emergency payment in their bank accounts, as Services Australia works to keep up with demand.
Prime Minister Scott Morrison - currently isolating after testing positive to COVID-19 - says the defence force is pre-positioned in Sydney and Nowra where flash flooding is expected.
The ADF has so far rescued 91 people during 36 missions in flood-stricken areas of Queensland and NSW.
"The ADF are highly active in assisting both response efforts and recovery and clean-up efforts, and there is much planning going on, on that front," Mr Morrison said on Facebook.
Meanwhile, Emergency Management Minister Bridget McKenzie has defended the government for not yet using its $4.8 billion emergency response fund.
She says it is a "future fund" for catastrophic events expected in coming years and $150 million has been put towards flood mitigation projects.
"We haven't had to draw on (the emergency response fund) yet because we haven't exhausted our other funding," she told Nine.
But Labor senator Murray Watt says none of the mitigation projects given funding by the government has started construction, and nor has any funding gone to disaster recovery.
He told ABC radio it is the third disaster season since the fund was established and there has been a "shocking" lack of preparation for the kinds of floods Queensland and NSW are experiencing.
Senator Watt said the government was also misrepresenting the amount of money spent on disasters in the past three years by including $13 billion in support spent during the pandemic.
"Certainly (COVID) is a disaster, but the fact that the government has to roll in COVID support payments to bump up their disaster support figures shows they haven't done enough to support people recovering from natural disasters," he said.
The flooding has taken nine lives in Queensland and four in NSW.
