The Government has expressed its confidence in the Garda Síochána Ombudsman Commission (GSOC) and its chairman Simon O'Brien, despite concerns about his handling of the bugging controversy. "I have no beef with GSOC," Minister for Justice Alan Shatter told the Dáil on Tuesday night at the end of a debate on the controversy over alleged surveillance at the organisation's headquarters in Dublin.

During the debate, the Minister said Mr O’Brien’s failure to report to him on the security checks at the GSOC was “a matter of substantial concern to me” but he went on to express his backing for the commission and its work.

The GSOC commissioner Kieran Fitzgerald has said the watchdog “cannot definitively say we were bugged”. However, its advice was that the possibility of there being a benign explanation for some anomalies found during the sweep of its offices was “remote to zero”.

“What we are faced with at the conclusion of this is that we could more or less dismiss some of these threats, on the balance of probabilities. On others, we just do not know.”

Speaking on RTÉ’s Primetime, he said the reason it specifically pointed out there was no evidence of Garda wrongdoing in the matter was because there was much public speculation about the force possibly being involved.

“It is unfair for people to point fingers at the Garda on the basis of anything we have said or done,” he added.

It had not taken its findings to Mr Shatter because it had uncovered no definitive evidence. As the body that oversees the Garda, it would have been “illogical” to go to the force with is suspicions, precisely because the Garda would be regarded as a suspect for the bugging.

Earlier, the Association of Garda Sergeants and Inspectors called on the GSOC chairman Mr O’Brien to resign, saying he should “consider his position” after the commission had “usurped” the Government by not reporting the alleged surveillance to Mr Shatter.

In the Dáil the Minister said it was only fair to note Mr O’Brien had expressed regret when they met on Monday at the decision of the GSOC not to make such a report.

Both Mr Shatter and Taoiseach Enda Kenny rejected calls for an independent inquiry into the affair. Mr Kenny said they were asking him to set up an inquiry in advance of a meeting of the Oireachtas Public Service Oversight Committee today which would hear from the GSOC on the matter.

Informed sources said the GSOC would “stand by” its public statements to date on the matter at the committee tomorrow. “There were anomalies found, there wasn’t enough to go further with it but not going to the Government at the time was a mistake”.

Mr Shatter said the GSOC had informed him the issue had arisen following a routine security sweep last September at its Dublin offices that was not prompted by any specific concern. The sweep had identified two technical anomalies which raised a concern of a surveillance threat to the GSOC.

“I should emphasise that my understanding is that what was at issue were potential threats or vulnerabilities, not evidence that surveillance had, in fact, taken place. ”