Speaker Bronwyn Bishop has agreed to reimburse more than $5000 of taxpayers' money that she claimed in 2014 to charter a helicopter.
But she's standing by her argument that the $5227.27 claim was within the rules.
Mrs Bishop said in a statement on Thursday she had written to the Special Minister of State Michael Ronaldson indicating she would reimburse the costs associated with the November 5 trip.
"Whilst my understanding is that this travel was conducted within the rules, to avoid any doubt, I will reimburse the full costs," she said.
The helicopter was chartered from Melbourne to the Clifton Springs Golf Club - a journey of about 100 kilometres - to attend a Liberal Party fundraiser in the first week of the Victorian state election campaign.
Shortly after she issued her statement, Liberal frontbencher Christopher Pyne tweeted: "The Speaker, Bronwyn Bishop, is doing a superb job. She has my full support."
Earlier, Treasurer Joe Hockey said he did not believe the expense claim passed the "sniff test".
"Instinctively, it doesn't," he told Sydney radio station 2UE.
"It's not a good look and the Speaker should explain it."
Mr Hockey said he understood public outrage over the expense, noting people were entitled to call for Mrs Bishop's resignation.
Opposition Leader Bill Shorten added fuel to the fire, saying it was a gratuitous abuse of parliamentary entitlements.
"She thinks she is too important to drive down the Geelong road like hundreds of thousands of other Australians," he told reporters in Melbourne.
Mr Shorten called on Prime Minister Tony Abbott to say whether or not Mrs Bishop's use of her entitlements was appropriate.
Senator Ronaldson's office said presiding officers such as Mrs Bishop were entitled to submit expense claims directly to the Department of Finance and didn't require his approval.
"These charters can be aircraft, helicopters or other vehicles," a spokesman said.
The department form used for such claims specifies it must be for "office holder duties".
But Senator Ronaldson's approval must be sought by other MPs wanting to use special charters. For example, a rural backbencher may need to get to a capital city and there are no other scheduled services.
Meanwhile, the Speaker spent $130,889 on overseas travel in the later part of 2014.
This included $88,000 for a 16-day trip to Italy, Belgium, Austria and Switzerland for her unsuccessful campaigned to win the presidency of the Inter-Parliamentary Union, an international organisation headquartered in Geneva.
A spokesman for the Speaker said she would also be paying the 25 per cent loading which is applicable under new rules relating to amendments to erroneous travel claim declarations.
