TUNIS — Tunisia's ruling Islamist party Ennahda on Wednesday filed a bill that would prohibit blasphemy, said Habib Khedher, who heads the committee in charge of drafting the constitution.

"Today we went ahead with the filing of a bill that would criminalise blasphemy," said the lawyer, who is also an elected Ennahda MP in the National Constituent Assembly, Tunisia's interim parliament.

The bill envisages a prison sentence of up to two years, or four years for repeat offences, Khedher told a local radio station.

At its first congress to be held inside Tunisia in 24 years, the moderate Islamist party advocated the idea of outlawing offence to religion while also guaranteeing freedom of expression.

The bill filed on Wednesday draws up a list of subjects held sacred in the three Abrahamic religions, including God and the Prophet Mohammed, the earlier prophets, the holy books, mosques, churches and synagogues.

It also codifies the levels of offence to religious feeling in Islam, Christianity and Judaism, including "insults, profanity, derision and representation of Allah and Mohammed," something forbidden in Islam.

Khadher did not say when the bill would come up for debate, but it is likely to be a highly-charged session, with the government having already been criticised over the sensitive issue.

In a high-profile trial in May, a court slapped a small fine on the owner of the private Nessma television for undermining morality and public order by screening the Franco-Iranian film "Persepolis," which shows depictions of God.