Europe's top security and human rights watchdog has urged Ireland not to preserve blasphemous libel as a crime.

The OSCE said this would flout international free speech covenants.

Justice Minister Dermot Ahern said earlier this month that he would seek to amend the law that provides prison sentences for blasphemous libel, but could not abolish it altogether without a referendum to change the constitution.

The Defamation Bill of 2006 which is currently before the Dáil would repeal the 1961 Defamation Act, under which blasphemous libel can bring a jail term of seven years, but Mr Ahern is seeking to amend that.

He says a new law is needed instead due to a constitutional requirement to punish blasphemy.

Article 40.6.1.1 of the Constitution provides that ‘The publication or utterance of blasphemous, seditious, or indecent matter is an offence which shall be punishable in accordance with law.’

The media freedoms overseer in the 56-nation Organisation for Security and Cooperation in Europe welcomed Ireland's plan to decriminalise defamation in the legislation, but he said that inserting a new article for blasphemous libel was wrong.

Milos Haraszti said he had written to Mr Ahern and the heads of both houses of the Oireachtas urging them to enact the Defamation Bill without a clause for blasphemy, for which the minister has proposed a fine of up to €100,000.

‘It is clear that the Government's gesture of passing a new version of the blasphemy article, even if milder than the dormant old version, might incite new court cases and thereby exercise a chilling effect on freedom of expression,’ Mr Haraszti said.

His statement was published on the Vienna-based OSCE's website.

He said a blasphemy law violated international standards upholding the right to freely discuss issues of religion.