Barnaby Joyce is checking his travel records from 2011 to see if there are any "ambiguities" in his claim of expenses to attend a friend's wedding.
The Agriculture Minister compares his attendance at shock jock Michael Smith's wedding with going to a football match, saying both are work-related because politics get discussed.
Nevertheless, he's looking over his records to see if there are any expenses he should repay.
Attorney-General George Brandis on Sunday paid back almost $1700 claimed in parliamentary expenses to go to the 2011 wedding of the former 2UE radio host.
Senator Brandis said his attendance was "primarily professional", because Mr Smith had been covering scandals involving then Prime Minister Julia Gillard and Craig Thomson.
Mr Joyce said on Monday his initial investigations showed he didn't use a flight to travel to the wedding on the NSW north coast, use a Comcar to drive from his hotel to the wedding nor charge taxpayers for the cost of his hotel room.
"If there was any ambiguity about going from the Andrew Bolt Show to the motel ... I'll refund it but it was a work day like any other day," he told the ABC.
He said a range of people "involved with politics and involved in journalism" attended the wedding.
He likened it to getting invited to watch a football game or attend formal events.
"They're all private functions at which you spend most of the time talking about politics."
Acting Labor leader Chris Bowen said Senator Brandis should not be involved in drawing up the new ministerial code of conduct since he'd breached the old code "so flagrantly".
Mr Bowen conceded there were some ambiguous functions politicians attended that were a mix of work and pleasure but said a "mate's wedding" clearly was not one.
"To see the first law officer of the nation claim that a friend's wedding in which he reportedly, quote unquote, 'tore up the dance floor', was a work-related expense is pathetic," he said.
"He's clearly one of the parliament's now biggest hypocrites."
Asked if Senator Brandis "tore up the dance floor", Mr Joyce said: "My recollection is not that astute."