Mr Abbott himself has in the last couple of days paid back more than $1700 he claimed seven years ago for attending the weddings of two Liberal Party colleagues.
He's repaid the $1094 claimed for a trip to rural Victoria to see former frontbencher Sophie Mirabella get married and $609 for attending then MP Peter Slipper's wedding, both in 2006.
"When the controversy arose after the Michael Smith wedding I remembered that some seven years ago I had been to a couple of weddings," he told reporters in Bali on Monday.
Mr Abbott checked his records, sought advice and was told it was unclear whether or not he was entitled to bill taxpayers for the trips.
"In order to avoid doubt, I paid the relevant money back," he said.
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The refund comes a week after Attorney-General George Brandis and Agriculture Minister Barnaby Joyce repaid a total of almost $2300 for their travel costs to attend the 2011 wedding of former radio presenter Michael Smith.
Mr Joyce again faced questions for attending the wedding of billionaire Gina Rinehart's business partner's granddaughter.
Ms Rinehart flew Mr Joyce, fellow minister Julie Bishop and Liberal MP Teresa Gambaro from Perth to India in a private jet for the event in June 2011.
The three MPs then billed taxpayers for more than $12,000 for their trips home, which they said incorporated study trips.
Mr Joyce said critics are just trying to "level the score against the coalition" by bringing up the claims from several years ago.
"We never did anything illegal. You did everything that you were basically entitled to do," he said on Monday.
He defended his decision to combine the wedding with a study tour to Malaysia, saying it was actually made cheaper for taxpayers since Ms Rinehart paid for half the trip.
But Mr Joyce has now repaid this money.
Mr Abbott said politicians must ensure they act within their entitlements.
"They should err on the side of caution and if there's any doubt they should act immediately to clear the matter up," he said.
Mr Joyce suggested MPs' expense entitlements needed more clarity and reform to address grey areas.
The Australian Greens are proposing new legislation to set up a National Integrity Commission and the appointment of an independent parliamentary officer to give advice on entitlements.
Former Howard government minister Peter Reith defended the right of MPs to attending weddings and bill taxpayers for their travel costs.
"Getting to know someone on a personal, intimate basis can be a very important part of what you do as a politician," he told ABC television on Monday.
Mr Reith said in government he attended the wedding of a senior Melbourne business figure.
But former federal coalition leader John Hewson says if the government wants the public to believe it can control expenditure, MPs shouldn't waste taxpayers' money on their personal lives.
In opposition, the coalition pursued Mr Slipper when he was house speaker over the alleged misuse of Cabcharge dockets to pay for $900 worth of travel to Canberra region wineries.
Mr Slipper has pleaded not guilty to the charges.
