Garda Siochána alleged to be monitoring phone calls and threatening reporters with arrest in attempt to reveal sources

Journalists in Ireland have raised concerns about the country's draconian gagging orders on police officers talking to the media, including allegations that the state is monitoring their mobile phone calls to try to reveal sources.

Dublin-based reporters, some of whom are under death threats from armed criminal gangs, have told MediaGuardian that the Irish police force, Garda Siochána, has questioned them about police contacts, threatened them with arrest and has been checking their mobile phone calls to suspected sources.

One reporter said he has been questioned 30 times in just over a decade and was under sustained pressure to reveal his sources.

Ian Mallon, the deputy editor of Dublin's Evening Herald newspaper, said the gardaí appeared more interested in who was the source of his stories than in acting against a crime boss who put a €20,000 (£16,000) bounty on the head of his colleague Mick McCaffrey.

Mallon described the Garda's ongoing pursuit of journalists' sources in the Republic as "Stasi-like".

The human rights organisation Index on Censorship said the Irish Republic's 2005 Garda Siochána Act, especially clause 62 of the legislation outlawing most rank and file police contact with the media, was "not the behaviour of a European democracy".

Under the act, Irish police officers who speak to journalists without authorisation from their superiors can face fines of up to €75,000, dismissal from the force or even seven years in prison.

Index on Censorship described the act and the recent upsurge in gardaí pursuing journalists over their sources as akin to "the kind of behaviour one would expect in an unreconstructed dictatorship".

An Index spokesman, Padraig Reidy, said: "Reporters should not be forced to operate in fear of police surveillance."

Reidy said Irish reporters were already under enough pressure from drugs gangs engaged in violent turf wars in Dublin and Limerick.

"It's bad enough worrying about being the next Veronica Guerin [the Dublin crime reporter murdered by Irish gangsters in 1996] without the extra concern of being hauled in by police for simply doing your job," he said.

Reidy warned that in reforming the relationship between the UK police and media after the phone hacking scandals, the British government should resist the Irish model.

"The Leveson inquiry should resist the temptation to further regulate journalists' access to contacts in the police and other state and security bodies," Reidy said. "The Irish situation shows how this can lead to paranoid police attempting to cover their own backs by harassing journalists."

Mallon said he was expecting to be questioned by detectives who want him to reveal his source behind last November's stories in the Evening Herald detailing the death threat to McCaffrey.

"We sat on that story for weeks and even informed the Garda that we had been told this gangster put a hit out against Mick over a story he had written about this criminal. We were most co-operative," he added.

"Our story was about another journalist in this city facing a death threat from criminals and yet I am to be questioned about who leaked the story to us. That's absurd. They were more concerned to find how they could trace back the source. It is Stasi-like behaviour and totally paranoid and censorious."

MediaGuardian has learned that the information about threats to McCaffrey's life was intercepted through secret Garda wire tappings – information that cannot be used as evidence in court.

Many experienced Garda sources now use cheap, disposable mobile phones to keep in touch with reporters.

The veteran crime and security journalist Jim Cusack, from the Sunday Independent, said he has faced threats of detention over his refusal to reveal sources in a story about a Real IRA murder.

Cusack said: "I have been threatened with possible arrest for 'withholding information relating to a criminal offence' – the 2005 act again – with a punishment of up to 10 years when I told gardaí I could not remember the source of a story about a dissident murder in Donegal several months earlier.

"The last time I was made aware my phone records were being hacked was last year after I contacted a detective involved in a murder case and left a message referring to some material I had come across which might be of use in the case.

"I was not called back. Instead a third party contacted me and said the detective had been warned by a colleague that my phone was under surveillance and the call had been logged by C3. This is the old name for the Garda security and intelligence section."

Asked about both the continued gagging of gardaí talking to the media and allegations of journalists being threatened with arrest as well coming under covert surveillance, the Garda press office said: "An Garda Siochána do not discuss internal discipline matters." The force's press office declined to answer specific queries about journalists alleging their calls were being monitored.

The Irish Department of Justice defended the use of the act and said there were no plans to amend it despite promises to enact new laws to protect whistleblowers. The department added that the act prevented the disclosure of information that "could impede an investigation and potentially a prosecution".

A spokesman for the department said: "By its nature, police work requires a high level of confidentiality to protect witnesses, victims and gardaí. In order for policing to be effective, the public must feel they can communicate openly with their local gardaí and trust that the information they provide will be protected and treated appropriately."

Michael O'Toole, the crime correspondent of the Irish Daily Star, urged the UK media to oppose any attempt to bring in a law like the 2005 Garda Siochána Act.

O'Toole said that in reforming the relationship between the Metropolitan police and News International "the baby should not be thrown out with the bath water". He revealed he has been questioned 30 times in 12 years by gardaí about sources. The last time was in 2011 when he obtained exclusive pictures of a riot inside Dublin's Mountjoy prison.

"I take it as read that my phone calls are being listened into, that my records are being checked to see if I am talking to any Garda officers. What went on between the Met in London and certain journalists was corrupt and wrong. But take a look at the opposite side of the coin here in Ireland and this paranoia infecting everything."