PM and treasurer bill taxpayers for private jet to Lachlan Murdoch's Christmas party

Scott Morrison and Josh Frydenberg billed taxpayers almost $5,000 to take the prime minister’s private jet on a whirlwind trip to Sydney on the night of Lachlan Murdoch’s Christmas party, leaving Canberra after 6pm, attending the Bellevue Hill soiree and then returning to the capital before 9am the next morning.

On 5 December last year, as bushfires blanketed Sydney in smoke haze, both the prime minister and treasurer attended the media heir’s mansion, Le Manoir, in the harbourside suburb.

The party was filled with celebrities, rich-listers and politicians, including Australia’s richest man, Anthony Pratt, the former NSW premier Mike Baird and the Crown casino boss, John Alexander.

The party, according to media reports, began about 5pm. Morrison and Frydenberg were in parliament until at least 6pm for the last day of the sitting year.

Related: RAAF jet is protecting Mathias Cormann from Covid-19, Morrison says

Flight logs published by the Department of Defence show the pair, along with ministers Peter Dutton and Stuart Robert, took the jet to Sydney at a cost of $2,153. Dutton did not respond to questions about whether he attended the party. Robert was in Sydney for official parliamentary business and did not attend the party.

Media reports show that both Morrison and Frydenberg did attend. While in Sydney, Frydenberg charged taxpayers for the use of Comcars, but not any additional expenses for accommodation.

Early the next morning, records show Morrison, Frydenberg and Dutton flew back to Canberra, again on the jet, this time at a cost of $2,583.

Morrison and Dutton arrived back in time to hold a media event at 9am at Canberra airport to discuss new anti-terrorism measures.

Frydenberg then billed taxpayers $486 to fly home to Melbourne from Canberra, while Dutton flew home to Brisbane, again via Sydney, at a cost of $831.

The use of the prime minister’s jet alone cost about $4,736. The trip to Sydney cannot have lasted more than 14 hours.

​The Boeing 737 Business Jet is one of six RAAF “special purpose” planes used by senior ministers and dignitaries when commercial flights are either unavailable or deemed unsuitable for the journey.

The former finance minister Mathias Cormann has been given the use of a Dassault Falcon 7X aircraft from the same fleet to travel around Europe as part of his bid for the top job at the OECD, costing taxpayers a reported $4,300 per hour. The final bill for Cormann’s use of the aircraft won’t be known until next year when the Department of Defence publishes flight logs for 2020.

The rules on using the special purpose aircraft require that it be done for the dominant purpose of parliamentary business and the expense must represent value for money.

Morrison lives in Sydney and was travelling with his family from Canberra, giving him at least some explanation for the trip.

But Frydenberg, despite repeated questions from the Guardian, has failed to explain how his trip to Sydney constituted parliamentary business or answer whether the Murdoch party was his primary purpose for travel.

There is no other public record of Frydenberg engaging in official business while in Sydney, nor was there much of a time window to conduct any such business, given the hour at which they flew back to Canberra the morning after the Murdoch party.

In 2017, following an expenses scandal involving Sussan Ley, the former prime minister Malcolm Turnbull introduced new rules governing the use of expenses.

The new expenses regime introduced a formal “pub test” – meaning MPs should consider “how the public would perceive their use” of travel resources – and also required them to be prepared to publicly justify their expenses.

“Australians are entitled to expect that politicians spend taxpayers’ money carefully, ensuring at all times that their work expenditure represents an efficient, effective and ethical use of public resources,” Turnbull said at the time.

“We should be, as politicians, backbenchers and ministers, we should be as careful and as accountable with taxpayers’ money as we possibly can be.”

Comment was sought from the offices of Morrison, Dutton, Frydenberg and Robert. A spokesman for Robert was the only one to respond, giving a schedule of official business conducted in Sydney and confirming non-attendance at the party.