Facing the first question time since the events in February - and as parts of NSW are again evacuated due to heavy rain - Mr Morrison said 1.4 million Australians have so far received assistance totalling $1.3 billion.

But opposition members asked Mr Morrison why it took the resignation of NSW Liberal MP Catherine Cusack for the government to provide funding to more flood-hit communities.

Ms Cusack resigned from the party to protest federal government allocation of funding to flood victims, claiming it was based on whether they lived in a seat held by the Liberal, National or Labor party.

Mr Morrison rejected the claim and said many areas were being considered for further funding before Ms Cusack resigned.

"Further assessments were being done on other local government areas in that region and once those assessments were complete, then a further decision would be made," he said.

The prime minister was also criticised for providing extra support in NSW over Queensland.

But he said it was due to the scale of the flood in NSW being "materially different" to the flood in Queensland.

"The decision was taken to provide assistance above and beyond the normal responses to floods for the Northern Rivers because it was a one-in-500-year flood, more than two metres higher than the highest flood ever experienced," he said.

Opposition Leader Anthony Albanese says the government needs to act on disaster mitigation to ensure Australia is prepared for these events in the future.

"These one-in-100, 200, 500-year events are happening pretty frequently and it's called climate change," he said.

"Every event in Australia is not because of climate change ... but the events are more extreme and more regular."

Australian Associated Press