Scott Morrison is expected to declare a national emergency on Wednesday in response to the devastating floods in northern NSW.

After finishing a week in Covid-19 isolation, the prime minister is travelling to the hard-hit city of Lismore with NSW Premier Dominic Perrottet.

Lismore has been among the regional areas devastated by floods, where four people have died, hundreds displaced and thousands of homes and businesses destroyed.

"The flooding disaster across south-east Queensland and NSW is absolutely devastating," Mr Morrison tweeted on Tuesday.

"While the clean-up and recovery is well underway for some, many areas particularly around Lismore remain isolated ... and critical supplies being airlifted in."

Governor-General David Hurley is expected on Wednesday to approve the declaration of a national emergency on the advice of the PM.

It will be the first such declaration since laws passed in December 2020 allowing a national emergency to be declared "where an emergency has occurred, is occurring or is likely to occur, and it has caused, is causing or is likely to cause nationally significant harm".

The idea of a national emergency declaration came out of the Black Summer bushfires royal commission, which noted Australia's disaster outlook "is alarming".

What does declaring a national emergency mean?

The laws allow ministers to "suspend, vary or substitute 'red tape' requirements in laws that they administer, where doing so would be of benefit to the public, or a section of the public, during a national emergency".

This can include such things as removing barriers to people in emergency-affected areas accessing payments, benefits or services without the need for ID documents or witnessed signatures.

It also allows the prime minister to find out what stockpiles, assets and resources the government has at its disposal, whether stockpiles need supplementing, and what could be made available to assist in the recovery.

Flood victims 'completely abandoned' by Australian government

Mr Morrison has been criticised for not declaring a state of emergency last week as floodwaters tore through southeast Queensland and northern NSW.

Murray Watt, a Queensland Labor senator who serves as the party's shadow minister for natural disaster and emergency management, has been vocal about the urgent help needed in the areas.

"Three years ago, Scott Morrison announced a $4B Emergency Response Fund," he wrote on Twitter on Wednesday morning.

"He said it would protect Australians from disasters, but all it’s done is earn his government over $800M in interest. And now, flood victims are paying the price.

"Scott Morrison is never there when you need him."

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Senator Watt said the money should be used to instead build flood levees, improve drainage and other flood mitigation measures.

"After the Black Summer debacle, when Scott Morrison blamed the states for ADF deployment delays, the PM gave himself new powers to 'declare a national emergency'," he said just hours before the PM’s announcement.

"He said it would cut red tape and help mobilise resources post-disaster. Why hasn't he declared one now?"

People have been vocal about their frustrations with the Australian government, with Senator Watt telling ABC Radio they feel "completely abandoned".

"Every single person I speak to, basically the first thing they say to me is 'where is the government?'" he said, adding he hadn’t seen a single federal minister on the ground in three days in northern NSW.

"People felt completely abandoned by their government during the crisis itself and now they feel completely abounded as they begin the job of cleaning up and recovering."

Numerous people have poked fun at the prime minister's trip to Lismore, with one person posting a meme of Scott Morrison playing his ukulele while hitching a lift into town on a dinghie.

"We'll get to see exactly how angry Lismore folks are today when El Slobbo arrives and starts to bully people into shaking his hand," another person said.

"There is not a disaster Scott Morrison won't show up late for and make demonstrably worse with his presence," a woman Tweeted.

With AAP

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