Malcolm Turnbull has dismissed as fiction a claim he and Treasurer Scott Morrison were rolled by cabinet colleagues on reining in tax breaks for property investors.
"That story ... has no basis, in fact, at all," the prime minister told parliament on Wednesday, adding it was an invention.
"It is a reminder of Mark Twain's wise words that only fiction has to be credible. In this case it is not even credible."
Mr Turnbull was responding to revelations in a new book, The Turnbull Gamble, by The Australian writer Peter Van Onselen and academic Wayne Errington.
Van Onselen, in response to Mr Turnbull's denial, tweeted: "I invite all journalists to check with their own cabinet sources whether what we write happened re negative gearing is credible or not.."
Earlier Labor seized on claims Mr Turnbull and Mr Morrison argued in cabinet for tighter negative gearing tax concessions, before being rolled in a key budget committee.
"This goes to the lack of an economic agenda at the heart of the Turnbull government," shadow treasurer Chris Bowen told reporters.
The prime minister and treasurer were prepared to do and say anything to get through a political challenge, rather than provide the leadership Australian needed.
The book's authors wrote Mr Turnbull and Mr Morrison were "all in favour" of making changes to negative gearing, albeit in a "more considered" and "less extreme way" than Labor.
Labor's plan was to limit negative gearing to new homes from July 1 next year and halve the discount on capital gains tax.
In April, Mr Turnbull announced the government wouldn't support Labor's policy, arguing the changes would devalue every home in Australia.
Deputy Labor leader Tanya Plibersek said clearly there were some people in the Liberal Party who saw the sense of reining in negative gearing tax concessions.
"We shouldn't be giving more help to people to buy their 10th or their 30th house than we do to help people buy their first house," she said.
"I would certainly hope that sense prevails."
