Another Liberal MP has called out the prime minister's character, saying she cannot vote for a "a ruthless self-serving bully" and no longer recognises the party she joined.
NSW state Liberal MP Catherine Cusack attacked Scott Morrison's handling of the recent floods, accusing him of politicising the tragedy.
"I can't vote for Scott Morrison, full stop, at the next federal election," she told the ABC.
"Doing the right thing now won't get my vote because it won't undo the wrong he has done to my community."
Ms Cusack says Mr Morrison is using his role as prime minister to bully the NSW government and flood victims because he is not getting his way.
This was evident in the political appointment of Shane Stone as the co-ordinator-general of the National Recovery and Resilience Agency and using guidelines to exclude some flood victims, she said.
The upper house member also accused Mr Morrison of failing to engage with the NSW government on assessing and approving payments and co-funding a recent disaster package.
"As a result, those packages are well below what's required and what should be available," she said.
"It is unbelievable anyone would act like this towards flood victims."
Mr Morrison told reporters in Sydney the federal government had invested $2.1 billion on the NSW flood response.
But he said there were some programs which would be fully funded by the state and some for which the cost would be shared with the commonwealth.
Assistant minister Tim Wilson defended the prime minister, saying there would always be "people who will be upset or disgruntled about previous experiences".
"I've always found my engagements with him (Mr Morrison) to be incredibly professional and engaged in good faith," he said.
A new poll put Labor 14 points ahead of the coalition, in the wake of NSW Liberal senator Concetta Fierravanti-Wells criticising the prime minister's character and trustworthiness.
A Roy Morgan poll conducted in the past week shows the ALP extending its lead to 57-43 in two-party preferred terms - a 1.5 percentage point increase from a week prior.
Senior Labor figures are trying to play down their lead in the polls, with frontbencher Chris Bowen saying the party needed to "win seats, not polls".
Labor leader Anthony Albanese admitted his party had a mountain to climb, having only won from opposition three times since World War II.
"I'm only worried about a poll on polling day," he said.
"We are putting forward a constructive plan for the nation's future - one where no one is held back and no one is left behind."
Mr Morrison sought to turn attention to the relief the government's 22-cents a litre cut to the fuel excise was providing.
"We are seeing ... (price) falls already - all around the country," he said.
Shadow treasurer Jim Chalmers used a National Press Club address to attack stagnant wages growth under the coalition.
"If last week had been a Labor budget ... it would have invested in productivity, so we can grow the economy more strongly without runaway inflation," he said.
