Former Minister for Justice Gerry Collins has told the Smithwick Tribunal that the possibility of an IRA mole within An Garda Síochána was never raised with him by either his political counterparts in the north or the RUC at regular meetings.
The former minister acknowledged it would have been highly embarrassing if there was such a mole but he insisted the issue never arose.
He said the cross-border meetings were "no holds barred" events and it would have been raised if there was a concern.
The Smithwick Tribunal is investigating whether a garda in Dundalk informed the IRA about a meeting with two senior RUC officers in the station on the afternoon of 20 March 1989.
The two men, Chief Supt Harry Breen and Supt Bob Buchanan were killed in an IRA ambush just minutes after leaving the garda station.
Three garda in particular are being examined, former Det Sgt Owen Corrigan and former sergeants Leo Colton and Finbarr Hickey. All three deny any claims of collusion with the IRA.
He said the day after the killing, the Cabinet asked the Garda Commissioner to look into the murders. Assistant Commissioner Ned O'Dea was sent to Dundalk to talk to all gardai in the station on the day of 20 March.
He was asked by Mary Laverty, senior counsel for the Tribunal, if this investigation was set up to look at whether there was a mole. In reply he said it was asked to discover all facts relating to the deaths of the two men.
Meanwhile, in a judgment delivered this afternoon, Judge Peter Smithwick rejected an application by the Garda Commissioner to have a report heard in private.
The report was written by then Detective Supt Michael Finnegan and it related to the circumstances surrounding the abduction of Owen Corrigan in 1995.
Counsel for the Commissioner, Michael Durak had said the document should be privileged and therefore not read out in public as it was prepared in advance of litigation and contained intelligence matters relating to the security of the State.
However, the Judge rejected both grounds and said the report and its author could be heard in open session.
Earlier the Tribunal judge confirmed that the former Assist Garda Commissioner Kevin Carty would be appearing to give evidence.
Mr Carty had been due to give evidence last week but failed to show up.
The judge said there had been a breakdown in communications and Mr Carty had furnished them with an address in Eastern Europe where he could be contacted.
The former garda had been in touch with the Tribunal and said he did not intend any disrespect by his non-appearance last week, the Judge said.
The Tribunal has also said it was not responsible for the appearance of a statement on the internet by a key witness, Ian Hurst.
In the statement, Mr Hurst outlines his background and how he worked for British military intelligence in the north in an organisation called the Force Research Unit.
In the statement, Mr Hurst claims that several of the IRA members who carried out the ambush on the RUC men were likely to be informers for various British security organisations.
