Michael Smith has rushed to the defence of Coalition frontbencher George Brandis, who has been accused of hypocrisy for claiming taxpayer funds to attend the ex-shock jock’s wedding.

Smith — who has hounded union officials, including Craig Thomson, for allegedly misappropriating members’ funds — says Brandis’ expenses claim was an innocent mistake and there is a grey area when it comes to what politicians can and cannot claim as work-related travel.

“Does it display incompetence? Does it display dishonesty? Does it display a slap-dash approach? I don’t see any of that on the evidence,” Smith told Crikey.

“A literal reading of the guidelines doesn’t include meetings with journalists. But the vast majority of what Brandis did at the wedding falls within the work-related expense arena. He had a sincere belief he was going in a professional capacity and to network with journalists. I know the bloke and I know when he said it was a legitimate claim he believed it.”

The former 2UE host, who departed the station after trying to pursue Julia Gillard’s role in a 1990s union scandal, compared being a guest at his 2011 wedding to appearing on the ABC’s Q&A program. Around a dozen journalists attended the wedding between Smith and Australian Financial Review life and leisure editor Katarina Kroslakova. Coalition frontbencher Barnaby Joyce also attended.

While Smith and Brandis have been described as friends, Smith says their relationship has been a professional one. The pair worked closely together pursuing the Thomson affair, but had not been to each others’ houses, according to Smith. Brandis gave a wedding speech covering freedom of speech issues (including Smith’s departure from 2UE) rather than personal matters. Smith claimed at the time that Brandis had torn up the dance floor after the wedding.

Smith says Brandis’ decision to pay back the $1683 he claimed for attending the wedding should not be read as a concession he did anything wrong. “I think it’s a reaction to community response,” he said. “It’s in no way an admission of anything.”

Smith added that he believes Joyce has been “smeared terribly and unfairly” by being named prominently in Fairfax’s initial reports breaking the story. Joyce has said he did not drive to the wedding, did not use a Comcar to drive from his hotel to the wedding and didn’t charge taxpayers for the cost of his hotel room.

Acting Opposition Leader Chris Bowen this morning slammed Brandis as “pathetic” and one of Parliament’s “biggest hypocrites” for claiming taxpayer funds to attend the wedding while acting as a watchdog on parliamentary standards.

As covered in a Crikey profile last year, Smith has become an prolific blogger and played an active role in reviving the Australian Workers Union slush fund scandal since his acrimonious departure from 2UE.