The chairman of the Public Accounts Committee has said he is “damn sure” leaks about his expenses claims from the officials in the Department of Enterprise Trade and Employment.

John McGuinness was responding to questions from members of the committee about his expenses claims while a junior minister.

He defended his requests for his wife to travel on a trade mission with him and a subsequent business class trip they took together and overtime paid to his son when he worked as an assistant in the Dáil.

Mr McGuinness has been under pressure to step down from his role at the powerful accounts watchdog amid repeated reports on how money was spent while he was a junior minister.

Fine Gael’s John Deasy said senior figures in Government thought Mr McGuinness had crossed the line in terms of his chairmanship and indicated he was therefore not surprised that documents relating to Mr McGuinness were released.

In response, Mr McGuinness said he was “damn sure” the documents were leaked by the department.

“I think that the nature of things in politics and the civil service,” he said.

“There are powerful forces that would not like to see a banking inquiry conducted or inquiry into other spending in the State who would prefer to have that lie .”

On foot of those comments both Independent TD Shane Ross and Mary Lou McDonald called for the Government to issue a statement clarifying that it supported the independence of the committee.

Several Government TDs objected to the thrust of those comments.

Labour deputy Derek Nolan said the meeting had descended into a farce and he was one of a number of Government TDs who stated categorically that they had never been approached by party colleagues with a view to influencing their role on the committee.

Earlier, in answer to the question of whether his credibility has been undermined and should he continue to chair the committee Mr McGuinness said “I have to say quite frankly I do not consider my credibility has been damaged.”

“In all that was there six years ago I acted appropriately. I do not feel that what was printed in relation to these matters damages how I might chair the committee.

“It does not change my views on what needs to be done. It will sharpen up my view on standards being applied today”.

Mr McGuinness also defended the €250,000 office development that was ordered by the Office of Public Works (OPW). But he accepted he would have handled things differently in hindsight. “Did I personally go out to do something wrong? Did I do things that were to deliberately benefit me or deliberately access the public purse? It wasn’t,” he said.

Mr McGuinness said he was not the only minister who travelled abroad on official duties with his wife at the time and that things were different “back then”.

He said a group of committee members, under the chairmanship of current Minister for Finance Michael Noonan, had travelled to Sacramento with their wives in 2008.

“I was on that group, our wives were taken with us and we paid for our wives,” he added. “That’s a fact and I’m sure that there are other examples that we can turn to. What seems to be unusual about travel is that it seems as if I did it and nobody else did in 2008. That’s not the case.”

Asked about his son’s overtime payment of €30,000 for one year, Mr McGuinness said it was to compensate for work that was required.

“Looking back at it now, it was a different country then in 2007,” Mr McGuinness told the committee. “What was acceptable back then is not acceptable now and I accept that.”

Referring to Mr McGuinness’s wife and son, Mr Ross said the McGuinness family had done well out of the State between 2007 and 2009.

Mr McGuinness strongly rejected that supposition, telling Mr Ross he did not know the effort that had been put in by his family.

Mr McGuinness said he would never set out to damage the committee because he has “far too much respect” for it. “If I’ve given the impression that you seem to have that I offended a member or that in a way I have damaged the committee, that was not intentional,” he said.

“I would not set out to do that and I do not believe myself to be bigger or better than anyone who sits here on this committee. “I happen to be chairman of the committee but I would happily serve as a member of the committee which I have done before.”

Mr McGuinness said there seemed to be a suggestion that he was the only minister to travel with a spouse in 2008. But he insisted that “lots of people” did so, and they reimbursed their respective departments or committees for the costs.

Mr McGuinness confirmed he took three trips with his wife, paid for by the State. These included two St Patrick’s Day trips to Seattle and Edinburgh, and a promotional event to London, of which he could not recall exact details. He rejected suggestions that he “intimidated” civil servants in correspondences requesting that his wife accompany him on trade missions to Dubai and Canada.

Mr McGuinness insisted that he had offered to pay for his wife’s share of the costs, but was stonewalled due to protocol. The chairman said he is not “a traveller by nature” and that he, upon taking his position, simply wanted to clarify procedure for “exceptional circumstances”. He said he was trying to challenge old ways, but that was six years ago, and that he would behave differently today.

Mr McGuinness had been accepted by the Fine Gael-Labour coalition to head the Public Accounts Committee in 2011 after being put forward by Fianna Fail. Mr Ross also ran for the job.

Additional reporting: PA