Garda Commissioner Martin Callinan has rejected criticisms of the force by the Garda Síochána Ombudsman Commission following its investigation into alleged collusion between members of the force and a convicted drug dealer.

The Ombudsman accused gardaí of delaying its investigation and expressed serious concern about informant handling procedures.

A report published this afternoon on the force's covert human intelligence system shows the High Court judge monitoring the system was satisfied gardaí are in substantial compliance.

The Minister for Justice this afternoon published the Ombudsman's "special report" to him, which strongly criticises the garda informant handling procedures, training, management and governance and recommends changes.

The Ombudsman is also seeking independent access to the garda PULSE computer system.

Minister Alan Shatter said after he has received the Commissioner's observations on the Ombudsman's report he will convene a meeting to make sure that any difficulties have been resolved.

The Ombudsman Commission accused gardaí of delaying its investigation into the case of Kieran Boylan, a convicted drug dealer against whom further drugs charges were dropped in July 2008.

The public interest inquiry examined the nature of the garda relationship with the drug dealer.

A file was sent to the Director of Public Prosecutions, who directed that nobody should face prosecution.

The Ombudsman has also decided that no gardaí should face disciplinary action.

The report took the Ombudsman over four years to complete. The DPP took four months to dismiss the report as insufficient to sustain a criminal prosecution.

The commission's investigation focused on whether or not gardaí colluded with Boylan in the movement and supply of drugs.

The convicted drug dealer faced six charges in connection with the seizure of €1.7m worth of cocaine and heroin at a transport yard in Co Louth in October 2005.

He was on bail at the time after he had been caught with €700,000 worth of cocaine and heroin in Dublin and Louth, for which he was subsequently sentenced to five years in prison.

However, on the last day of the court sittings in July 2008, the 2005 drugs charges against Boylan were dropped without explanation.

The Ombudsman's investigation into why those charges were dropped also examined the nature of Boylan's relationship with gardaí.

It sought to establish whether or not he was acting as an informant for gardaí, registered or not.

The Ombudsman investigated whether or not any gardaí knew he was dealing drugs while acting as an informant; if he supplied drugs to other drug dealers and then gave information about those drugs to the gardaí; and whether or not a conviction secured on the basis of such information is now unsafe.

However, the DPP directed that no gardaí should face prosecution and that there was not sufficient evidence to support claims that convictions connected to Boylan were unsafe.

The Ombudsman today accused gardaí of repeated delay and debate and not supplying all the information within the 30-day agreed time frame.

However, it acknowledged that it got all but one of the documents it sought.