Press Ombudsman Susan McKay has issued a stern warning to politicians who take legal action when other forms of redress are available.
"Politicians, whatever their party background, who choose to sue rather than making a complaint through the Office of the Press Ombudsman, need to ask themselves if this is in the public interest," she said.
It comes as Sinn Féin TD Chris Andrews is suing both the Irish Times and its political correspondent Harry McGee personally over an article published last month.
The Press Council of Ireland and the Office of the Press Ombudsman issued a statement deploring the practices of "powerful public figures" suing individual journalists in response to public interest news reporting.
Earlier this week Taoiseach Leo Varadkar said "people are entitled to sue the media, but they don't have to”.
Welcoming Mr Varadkar's intervention, Ms McKay said her office provides a service that is "free and open to everyone" and which responds swiftly to all complaints.
"We welcome the Taoiseach's and the NUJ's support for journalists who are subject to this intimidating practice, and in this regard we are active participants in EU-wide efforts to prevent the use of Strategic Lawsuits Against Public Participation [SLAPP]," she said.
She added that the press is already struggling against a range of difficult circumstances.
Chair of the Press Council Rory Montgomery also welcomed the Taoiseach's remarks.
"While we respect the right of all individuals to defend their good name, and to use the law if they consider it necessary, we urge public figures and in particular public representatives to follow his advice," he said.
Tánaiste Micheál Martin said he is very concerned about the “chilling effect” of suing media and journalists by Sinn Féin.
"I'm at a loss as to what defamation has occurred here, but I'm not a lawyer, I accept that. But one has to take a balanced perspective on this," he said.
There was no response available from Sinn Féin regarding the remarks, but a spokesman said earlier this week that people are taking such cases when there is “no option but to vindicate their good name in the face of false accusations made by others”.