Figures from the Insurance Council of Australia estimate the cost of claims stemming from the disaster is now $1.45 billion and expected to rise further once the full extent of the damage is known.

The council said insurers had so far received more than 96,000 claims, with 80 per cent of those for homes.

Council chief executive Andrew Hall said there was an influx of claims coming from NSW.

"Insurers are prioritising those customers whose situation is the most severe to support them getting back on their feet as soon as possible," he said.

"This means it may take a few weeks for insurers to start the assessment process for less severe claims, but those customers can be assured their insurer is there to support them."

So far, 69 per cent of claims related to the flooding disaster have come from Queensland, while 31 per cent have come from NSW.

Meanwhile, an extra 680 ADF personnel were expected to be on the ground in northern NSW by the end of Tuesday, as communities seek to repair significant amounts of damage.

It's expected there will be as many as 5000 ADF personnel deployed across flood-ravaged areas by the end of the week.

Despite the increase in ADF support, there has been mounting criticism from affected residents that the government had been too slow to act in sending in defence troops to assist recovery efforts.

Flooding has also affected large parts of Sydney, with evacuation orders given for multiple areas in the city.

Prime Minister Scott Morrison, who is set to leave COVID isolation on Wednesday morning, is expected to visit flood-affected areas in northern NSW in coming days.

Federal cabinet's expenditure review committee is examining what Mr Morrison described as "over and above measures" - disaster funding that is outside of the existing categories of support.

"The Australian government will stand with those communities in the northern rivers to support them as they clean up now and in the months and years ahead," he said.

"This is not just a flood event ... this is a catastrophe on a national scale."

As of Tuesday morning, more than $282 million in disaster payments to flood victims have been paid to 242,000 people.

Of that, $157 million has been paid to victims in NSW and $125 million in Queensland.

Opposition Leader Anthony Albanese criticised how the government has handled bringing in the ADF.

"Clearly, there have been issues here with people who were on the roofs of places for a long period of time. There's a need for an explanation," he said.

"Why are people having to pitch in and privately hire helicopters when the ADF have access to those resources? They are all questions that need answers."

Mr Albanese said the government had failed to use money from its emergency response fund.

Australian Associated Press