An opposition call for a tribunal of inquiry into alleged misconduct by garda∅ in Co Donegal is "in conflict with the law", the Minister for Justice, Mr O'Donoghue, has insisted in the Dβil.

He rejected accusations by the Opposition of a dereliction of duty in dealing with a case which had been described as "probably the most serious case of corruption and improper activity in the history of the Garda force".

He dismissed calls for a tribunal of inquiry, and rejected claims by Fine Gael's justice spokesman, Mr Alan Shatter, that he was appointing a senior counsel to investigate the case merely to prolong the uncertainty and to give the Minister extra breathing space.

The controversy follows the death five years ago of a local cattle dealer, Mr Richie Barron, which led to the arrest of a number of members of the McBrearty family who alleged Garda harassment. A murder investigation was subsequently dropped. Five years after his death, Mr Barron's body was exhumed and a new examination determined he had died in a hit-and-run incident.

The issue was raised by Mr Shatter, who said: "No other EU democracy would allow allegations of police misconduct such as those levelled against a small number of garda∅ in Donegal to fester and remain undetermined and unresolved for over four years".

Labour's deputy leader, Mr Brendan Howlin, said that if even only a fraction of what was alleged took place, "it would still represent probably the most serious case of corruption and improper activity in the history of the Garda force".

The Minister warned that "we intervene with the criminal process at our peril" and "we cannot disregard legal principle for political expediency". He added that there was nothing to be gained by jeopardising criminal and civil proceedings at this time.

He pointed out that one of the most important issues to be addressed was Mr Barron's death, and there was no conclusive evidence yet as to whether this was criminal or accidental in nature.

The Fine Gael spokesman said it was not clear that the eminent lawyer, appointed by the Minister to examine progress on the investigations, would have access to all the documentation available to the garda∅ in the three internal investigations, or other related files.

The debate concludes tonight.