Two Coalition members, including the Immigration Minister, have become the latest in a string of MPs to repay money claimed under the parliamentary entitlements scheme for attending a colleague's wedding.

Scott Morrison and Assistant Minister for Defence Stuart Robert have each repaid $354 claimed as travel allowance. It is believed they were at the wedding of WA Liberal MP Steve Irons.

Speaking to reporters on Friday, Mr Morrison was reluctant to give details about the claim but said it was for travel in 2011 and the funds had been repaid.

"I can tell you there was an inadvertent claim that was made and it's been rectified," he said. "It was a pay back of $354."

When Mr Morrison was first asked about the expenses issue on Monday, he told Macquarie Radio host Ray Hadley he had not incorrectly claimed any entitlements.

Hadley asked: "Would you ever under any circumstance, if invited to a wedding, try and get some travel via the public purse?"

Mr Morrison responded: "Well I haven't, Ray."

On Friday morning, Mr Morrison sent a letter to the radio station saying that contrary to what he told the interviewer, he had in fact incorrectly claimed one night's travel allowance in October 2011, on the date of a colleague's wedding in Melbourne.

"At the time of responding to the question, I was not aware of this claim, and answered truthfully to the best of my recollection," the letter said.

Mr Morrison said he had been in Melbourne for the week and stayed an extra night to attend the wedding.

He said when his staff received the invoice for the accommodation, they completed a travel allowance claim for the entire week and he failed to pick up that the additional night should not have been claimed.

"I thought it was important to let you know about these matters as I have always had a very candid and upfront relationship [with] you and your listeners and when I get something wrong, I will always seek to be up front about it."

Mr Robert says he went to a meeting on the day of the wedding but has repaid the money to avoid any ambiguity.

Growing list of MPs to repay money

Mr Morrison is the latest in a growing list of MPs to repay money either because they had incorrectly claimed it or were not sure whether their claims were within the guidelines.

He joins Prime Minister Tony Abbott who recently repaid $1,700 that he spent attending the weddings of former colleagues Sophie Mirabella and Peter Slipper.

Mr Abbott said he was prompted to act on his expenses after Attorney-General George Brandis repaid nearly $1,700 he claimed from the taxpayer to attend the wedding of radio announcer Michael Smith in 2011.

Agriculture Minister Barnaby Joyce also repaid $615 for using a taxpayer-funded car to attend the same wedding.

Labor's Mark Dreyfus had called for an investigation into the Coalition claims, but was forced to repay $460 he had claimed for being in Canberra when he was in fact on the ski fields.

Acting Opposition Leader Chris Bowen has called for a bipartisan review of the entitlement rules, but Mr Abbott does not believe it is needed.