Bronwyn Bishop is under pressure to fully explain what "official business" she was undertaking when she charged taxpayers for attending Sophie Mirabella's wedding after a fellow committee member questioned the Speaker's version of events.
Fairfax Media revealed last week that the Speaker, already on "probation" for use of her expenses, claimed $600 in return flights to Albury on a day that coincided with the wedding of her colleague, then-MP Sophie Mirabella.
Despite Prime Minister Tony Abbott having previously repaid more than $1000 entitlements claimed to attend the same wedding, Mrs Bishop has so far refused to repay the money.
She is instead standing by a signed declaration to bureaucrats that asserts she was in Albury on official business, specifically to research work-life balance for an inquiry by a parliamentary committee, of which she was then chair.
But a former member of the committee disputes that Mrs Bishop had any official reason to travel to Albury
"There was no decision of the committee authorising the chair to attend meetings in Albury," said Jennie George a former Labor MP who served on the standing committee of family and human services in 2006. "We never heard a report back.
"If it was formal committee business it would be recorded. I'm mystified."
Documents released under freedom-of-information laws show Mrs Bishop arrived in Albury at 4.45pm on a Friday night.
"If she was meeting with an organisation it would be in working hours and who would fly to meet one person?," Mrs George added.
Mrs Bishop was in Wangaratta – about an hour's drive – the following day for Sophie Mirabella's wedding. Mrs Bishop was back in Sydney, where she claimed a further $170 in a taxi ride, by 3pm Sunday.
The question of whom the speaker met in Albury and for what purpose is one the Speaker is refusing to answer despite mounting pressure.
According to a final report released in December 2006, the committee held no public hearings outside of capital cities.
Mr Abbott declined the opportunity to defend the Speaker's trip when questioned on Monday.
Mr Abbott in 2013 sought advice before repaying more than $1100 in travel costs and travelling allowance to attend Mrs Mirabella's nuptials.
He then issued a warning to his fellow Liberal MPs to follow his example by repaying doubtful expenditure.
