Taoiseach Enda Kenny has said the issue of calls to and from Garda stations being recorded may have implications for tribunals as well as court cases.

It is understood the Morris and Smithwick tribunals are those where there is a concern.

“I don’t know the scale of actual contents on those tapes but we’re concerned about it. It’s a serious issue where in some cases, court cases have been dealt with, others reaching as far as tribunals may have implications for some of the findings there,” Mr Kenny said today.

The Taoiseach added the matter was very serious and that was why a Commission of Investigation has been set up.

This afternoon, the Special Criminal Court ruled an IRA membership trial can proceed after a senior garda told the court that phone lines at Garda stations at Cahir and Clonmel, connected to the investigation, were not linked to a recording system.

The three-judge court has adjourned the trial until next Tuesday to allow the defendants to seek physical inspections of the stations, in Co Tipperary.

Thomas McMahon (31) and his co-accused Noel Noonan (34) were due to stand trial at the Special Criminal Court yesterday, but Isobel Kennedy SC said a matter had arisen “in light of recent events of which we are all aware”.

Meanwhile, speaking in Leixlip, Co Kildare today at the confirmation €5 billion has been spent on the upgrade of the Intel campus, Mr Kenny said he felt it was his duty to send a senior official, secretary general of the Department of Justice Brian Purcell, to Garda Headquarters to meet Martin Callinan.

Asked if Mr Purcell had been instructed to ask Mr Callinan to resign Mr Kenny replied: “The Commissioner should be aware of my feelings about the gravity of the information relayed to me by the Attorney General and I asked that the secretary general of the department of Justice inform the Commissioner of my feelings.”

Tánaiste Eamon Gilmore, attending the same event as Mr Kenny, said there was concern around the possible impact on cases where a conviction has already been secured.

“We’re working on the terms of reference for that and expect that we will have that completed very shortly and be moving as quickly as possible to the establishment of that commission of investigation so we can establish the full extent of this taping exercise.”

Independent TD Shane Ross told The Irish Times today he planned to ask the chairman of the Public Accounts Committee John McGuinness to request the former Garda Commissioners, Martin Callinan and Fachtna Murphy, to appear before the committee to explain the purchases of equipment for recording of the phone calls.

New equipment was purchased for this purpose in 2008. Mr Ross said the price of the tender, which has a current estimate is around €500,000, raised a question around the spending of public funds. He said officials from the Department of Justice should also be called before the PAC to explain the tender.

The terms of reference may not be ready until next month, the Government has said.

It was confirmed that while over 2,500 recordings have been collected, there is no conclusive information on how Garda stations were involved and the extent of the recording.

Government officials were yesterday working on the assumption that most of the larger stations, such as divisional headquarters, would have equipment installed.

Sources said that the terms of reference would probably include a mandate to ascertain how many stations were involved, when it was introduced, whether it was subject to any rules or procedures or internal regulations.

There will also be detailed terms that will allow inquiry into the content of recordings, and the identify of those who were the subject of recordings, including the possibility that privileged conversations between solicitors and clients were recorded.

Privately, senior Government politicians raised concerns that recordings which should have been disclosed under the discovery process in the past may not have been disclosed.

One senior Government figure suggested that a question might arise as to whether or not such recordings were made in Dundalk Garda station during the 1980s.

The practice went back to the 1980s and happened on a widespread basis but not all Garda stations were involved. Dundalk was a major station because of its proximity to the border and because there was a large presence of republican paramilitaries in the surrounding area.

While there is no evidence to confirm such recordings were made, the source raised the possibility that if they were, they should have been passed on to the three inquiries which have been conducted into the murders of RUC officers, Bob Buchanan and Harry Breen in the late 1980s.

As far back as 2003, the inquiry conducted by Canadian judge Peter Cory, was told that no recordings or records of phone calls existed for the day the two senior officers were shot. Subsequent inquiries were also similarly informed.

Mr Ross added that a key question was why the process was so widespread?

“This original procedure of recording calls to garda stations was meant for bomb threats in the 1970s and 1980s during the Northern Troubles. It seems to have now been extended to a large number of stations and used for completely different purposes.”

Pressure on the Coalition has eased after the apology in the Dáil by Minister for Justice Alan Shatter to the two Garda whistleblowers.

However, there is still concern in both Government parties over when Mr Shatter and Attorney General Máire Whelan first became aware of the widespread recording of phone calls to and from Garda stations and why the Cabinet had not been informed earlier.

Mr Shatter yesterday withdrew his earlier assertion in the Dáil that Garda whistleblowers Sgt Maurice McCabe and former garda John Wilson had failed to co-operate with an investigation into the penalty points system.

“It was never my intention to mislead the House and I believe it is appropriate that I apologise to both and withdraw the statements made,” he said.

“I am aware that the whistleblowers and others have issues with some remarks I made outside this House. It was not my intention to misrepresent any matter connected with this issue. I apologise for any offence that may have been caused by any other remarks made by me,” said Mr Shatter.

Sgt McCabe last night said he was glad the record of the Dáil had been corrected. Mr Wilson also welcomed the move, saying it was “a long time coming”.

In a separate speech earlier in the day, Mr Shatter gave an explanation as to why a letter sent earlier this month by former Garda commissioner Martin Callinan, outlining the scale of phone taping, failed to reach him until Monday afternoon.

He said his department received other correspondence about recordings but insisted he was not aware of the wider practice until he was briefed by officials on Monday evening.

TDs in both Coalition parties, particularly Labour, expressed some anxiety about why it had taken two weeks for officials at the department to inform the Minister.