After Prime Minister Anthony Albanese raised questions about whether the amount raised was legitimate, a spokesman for One Nation leader Pauline Hanson said the party would bring in analysts to confirm the "fire the liar" campaign's legitimacy.
An independent forensic audit being commissioned would show the fundraising effort was authentic, the spokesman said.
"Why would I call out the liar ... then go and do something like that myself? It would destroy me," Senator Hanson later said at a media event in Western Australia.
Mr Albanese questioned what evidence there was the party had actually raised the funds, and Labor operatives privately suggested One Nation's online donation counter might have been fraudulent.
"What evidence is there? It is an example of slogans being put forward, not substance," he told reporters in Sydney.
As of Thursday afternoon, One Nation said it had raised more than $2 million through its campaign, designed as a counter to a Labor fundraiser targeting the populist minor party.
The fundraising stoush comes amid increasing concern within coalition ranks about One Nation's booming popularity, with one MP suggesting the two parties should strike an agreement not to compete in key seats at the next election.
As polls put the combined One Nation, Liberal and National primary vote at almost 50 per cent, Liberal MP Tony Pasin told The Australian such an alliance would avoid splitting the conservative vote and bolster the chance of Labor losing the next federal election.
But Opposition Leader Angus Taylor said there was no deal on the table.
"There'll be no carve-up of seats, and what we're going to be doing is carving up the Labor party," Mr Taylor told reporters in Perth on Thursday.
"We'll go toe-to-toe in every seat in this country to win every vote we can."
Other Liberals, publicly and privately, echoed Mr Taylor's comments.
"Our job is to fight like hell, not roll over and (put) up white flags ... I haven't spoken to any colleague who's happy to stand aside for a One Nation MP," one Liberal told AAP.
In separate interviews, frontbenchers Tim Wilson and James Paterson warned against hitching the Liberal wagon to One Nation, arguing such a move could cause reputational risks.
"There will be no peace talks, there will be no surrender to Labor, to One Nation, or any other party," Mr Wilson told ABC Radio.
The opposition leader said Mr Pasin would remain in the shadow cabinet, despite what colleagues have described as "freelancing" on a seat-swap with One Nation.
Mr Taylor has previously left the door open to preferencing Senator Hanson's party, although his colleagues remain split on that option.
Former prime minister Tony Abbott, who recently resurrected his political career as Liberal Party president, has also endorsed preferencing One Nation.
The latest Newspoll shows One Nation - now the party with the largest primary vote in the country - poses an existential threat to the coalition, whose vote has collapsed to 18 per cent.
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