A Liberal backbencher says it's simply speculation to suggest newspaper reports of Peter Slipper's misuse of parliamentary entitlements is payback for his election as Deputy Speaker.
Mr Slipper infuriated his coalition colleagues in September by accepting Labor's nomination for the position.
The opposition had hoped to force the government to provide a deputy from its own ranks so Labor would be down a vote when the deputy was in the chair.
Liberal backbencher Teresa Gambaro on Wednesday was asked whether News Ltd reports that Mr Slipper had been forced to pay back more than $14,000 in entitlements was revenge.
"That's just speculation," she told Sky News.
"But look, the entitlements are there for a reason and members have to adhere to strict guidelines and that's very clear to members."
The matter was one "for the department of finance and Peter Slipper".
News Ltd has reported the possible misuse of taxpayers' money is being investigated by the department.
Parliamentary secretary David Bradbury said the allegations against Mr Slipper were old.
"Many of the entitlements, as I understand it, that are in question here relate back to the previous Howard government," he said, adding the Gillard government had tried to increase transparency surrounding entitlements.
Mr Slipper spent $835 of public funds in six months on magazines about fashion, gardening, food and aquariums, News Ltd said.
It alleges he breached rules by allowing his son Nicholas to use his Canberra-based car while studying at a school in Sydney.
The office of former prime minister John Howard was warned by senior Liberal MPs of an "inappropriate" relationship between Mr Slipper and a staff member, News Ltd said.
