Des Carville, the Davy adviser to Siteserv who co-ordinated its 2012 sale to a company controlled by Denis O’Brien, previously helped the prominent stockbroking firm to advise the billionaire such as on deals involving Esat, the telecoms company that made his fortune.

Mr Carville joined the Department of Finance 18 months after the Siteserv deal, where he oversees the State’s shareholding in Irish banks.

He declared a conflict of interest over his involvement with Siteserv before he joined. The Government says he has “has not been involved in any issues on the Siteserv transaction” such as approving parliamentary questions, reviewing freedom of information requests and all internal discussions on the matter.

Catherine Murphy, the Independent TD who has been prominent in querying the role of the Department and State-owned IBRC in selling Siteserv at a €105 million loss to taxpayers, has got further answers to parliamentary questions submitted to Mr Noonan.

Ms Murphy referred in her questions to Mr Carville’s past involvement with Mr O’Brien. Mr Noonan told her that Davy wrote to the department to confirm that Mr Carville had only advised Siteserv and had not provided any advice during the transaction to Mr O’Brien’s Millington company, the Isle of Man vehicle used to buy Siteserv.

“I would like to clarify that Davy Corporate Finance, in conjunction with KPMG Corporate Finance, were advising Siteserv exclusively,” Mr Noonan said.

Mr Carville was unavailable for comment last night.

Following the release of the replies to Ms Murphy, Davy also confirmed it “was not adviser to IBRC or Millington, each of whom had their own advisers” for the Siteserv deal.

“Davy Corporate Finance has very robust and highly regulated procedures which are rigidly adhered to, not least in this case which involved a substantial write down of bank debt,” it said.

‘Privileged information

Mr Noonan said his department does not monitor share dealing activity.

“The Deputy raises serious concerns regarding potential insider dealing . . . If the deputy has any information regarding insider dealing in Siteserv shares, I would suggest that she contact the Irish Stock Exchange, ” he said.

Davy said: “The allegations made in Dáil Eireann that senior executives in Davy acquired shares in Siteserv in the months leading up to this transaction are totally untrue.

“Davy would welcome any investigation that the appropriate regulatory authorities initiate in respect of sharedealings in Siteserv and are confident that any such investigation will prove these allegations to be totally without foundation.”