Serious complaints of corruption and malpractice within An Garda Síochána by members of the force have resulted in three investigations in the past 12 months.

A 'whistleblower' system to root out corruption within the gardaí became operational in March last year and Brian McCarthy, a former secretary general to President Mary McAleese, was appointed to receive confidential reports from gardaí about alleged corruption.

The Department of Justice confirmed that the whistleblower "has forwarded three confidential reports to the garda commissioner since the establishment of his office".

One of the three complaints forwarded to garda commissioner Fachtna Murphy was made by a male garda in Cavan who alleged that his colleagues failed to investigate serious crimes, including one of false imprisonment.

The Sunday Tribune has learned that two other complaints lodged to the whistleblower's officer were made by male officers in Dublin and the midlands.

The garda based in the midlands alleged a 'dereliction of duty' by some of his fellow officers while the Dublin-based garda complained that one of his superiors was deliberately pre­venting him from carrying out his duties.

The government introduced a whistleblowers' charter for gardaí after the Morris tribunal recommended that a system be set up to make it possible for an officer to pass on allegations of corruption in confidence to a trusted person.

However, Pat Rabbitte, the Labour justice spokesman, and Charlie Flanagan, his Fine Gael counterpart, have expressed concern about the transparency and efficiency of the whistleblower's office.

If a garda wants to make a complaint about a fellow officer, he must do so through his superiors, which presents "an obvious conflict", according to the two politicians.

Additionally, many gardaí are unaware of how to get in touch with the whistleblower – both TDs have been contacted by gardaí asking how to contact the confidential office.

"The fact that there are only three complaints being investigated bears out my point. There is too much mystery surrounding how to access it," Rabbitte said.

"I've had to advise gardaí that they have to go through the structure in their garda station if they want to make a complaint. This obviously is a deterrent for some gardaí."

Rabbitte said two gardaí who contacted him first went to the garda ombudsman, which is not permitted to deal with complaints by gardaí against their colleagues.

"When I made enquiries on behalf of someone, it took me a long time to finally discover that the whistleblower's office was based at the Department of Justice. I don't think it's practical to accept that a member of An Garda Síochána with a matter on his or her mind will want to go through their superiors. In most cases, it only acts as a deterrent," he added.