Australia's health minister has stepped down temporarily, to allow auditors to scour her expense accounts, after she bought an investment apartment while on a work trip, an embarrassing start to the year for Prime Minister Malcolm Turnbull.

In a statement issued on Monday, Turnbull said Health Minister Susan Ley would forgo her salary, until an investigation is completed.

"I expect the highest standards from my ministers in all aspects of their conduct, and especially the expenditure of public money," the Liberal Party prime minister said.

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Ley, who is also aged care minister and sport minister, has been fighting calls for her resignation since Friday, when it was revealed she made expense claims for several visits to the Gold Coast, a holiday destination in northeastern Queensland state.

During one of the visits, she reportedly purchased an investment property worth US$581,000 from a Liberal Party donor.

Australia's SBS news site reported that Ley also claimed travel costs to the Gold Coast for New Year's Eve celebrations in 2013 and 2014.

Ley said she had agreed to stand aside after a discussion with Turnbull, and had agreed to repay some claims for transport and accommodation when she bought the apartment.

'I have not broken any of the rules'

"I apologise for the distraction that this issue has caused," she told reporters. "I'm very confident that the investigation will show that I have not broken any of the rules."

The latest scandal comes as Turnbull languishes in polls and faces a restive party.

A Newspoll in Monday's Australian newspaper put the Liberal prime minister and his opposition Labour counterpart Bill Shorten as the least popular pair of national political leaders in 20 years.

In the year to come, Turnbull's Liberal Party-led government faces a fractious Senate that has so far stymied major progress on its legislative agenda, mainly focused on spending cuts and tax reforms aimed at balancing the national budget.

Turnbull has also struggled to keep the support of the hard-right of his own party, which still simmers with resentment since his toppling of the more conservative Tony Abbott as prime minister in a party-room coup in 2015.

Turnbull's government has also come under pressure in recent weeks for a heavy-handed approach to recouping social security debts.