The Tánaiste has said he is concerned about the "chilling effect" lawsuits against journalists can have.
He was commenting after it was reported that Sinn Féin Dublin Bay South TD Chris Andrews has lodged defamation proceedings against The Irish Times and its political correspondent Harry McGee in the High Court.
Speaking in Shanghai, Micheál Martin said he was not a legal expert, but he felt Sinn Féin politicians were reaching for a lawsuit as a first resort when they were criticised by journalists.
Mr Martin said: "It's part of a trend that Sinn Féin is now deploying in terms of shutting down commentary on what are legitimate public issues.
"That’s not good in a democracy, it can have a chilling effect on journalists and on media more generally.
"One always has a right to resort to the courts, but I’m not exactly clear what exactly is defamatory here in ... respect of Deputy Andrews’ tweet."
Mr Martin said he felt there was a certain "slowness" in Sinn Féin’s reaction to condemning Hamas’ actions in Israel on 7 October when 1,400 Israelis were killed, many of whom in extremely violent circumstances.
Commenting about an article that referenced a tweet by Mr Andrews, the Tánaiste said: "I think that’s fair comment, but this pattern now, quite a lot of politicians have been sued, and media and journalists and that does ... suppress full public discussion and issues of important political topics and so on.
"Within the world of politics, we’re all subject to criticism and adverse comment and that comes with...the nature of political discourse.
"But I would be very concerned about the chilling effect, this trend, this pattern which is very much part of a Sinn Féin operation is having on public debate."
Yesterday, the Taoiseach said that the rise in lawsuits personally targeting journalists is "frightening" and is "designed to make journalists afraid".
