Tunisia's resurgent Salafists have succeeded in disrupting a string of cultural events deemed un-Islamic, with artists and opposition media increasingly blaming the Islamist-led government for failing to rein them in.

The hardline Islamists on Wednesday prevented an Iranian group from performing at a Sufi music festival in Kairouan, south of Tunis, saying their Shiite chanting amounted to an attack on sacred Muslim values.

Although it did not trigger any violence, as happened when Salafists attacked a Tunis art gallery in June, it was at least the third such incident in just 10 days, coming in the middle of the festival season and the holy month of Ramadan.

Last week, the director of a festival at Gboullat, in the northern Beja region, announced he was cancelling the event under pressure notably from the Salafists -- who adhere to a strict interpretation of Islam similar to the one practised in Saudi Arabia.

Another festival had been cancelled at the end of July, in Sejnane, with the organisers again blaming radical Islamists, who interrupted the event, saying it was unacceptable during the month of Ramadan.

Then on Tuesday, the night before the Iranian group was barred from the stage, renowned Tunisian actor Lotfi Abdelli was prevented from performing his comedy act "100% Halal" by hardline Muslims who had occupied the auditorium.

No extremist group has get claimed responsibility for the string of cultural disruptions, and Ansar al-Sharia, the main Salafist organisation, refuses all contact with the media.

The security forces, meanwhile, have been swift to disperse anti-government protests in recent weeks but have appeared softer towards the Islamists, according to some, prompting suspicions about the complicity of the ruling Islamist party Ennahda.

"They leave the Salafists alone," said the Tunisian actress and playwright Leila Toubel.

"How can we believe that this government and Ennahda are not involved? I would like to think that there is nothing to it, but these people (the Salafists) go unpunished, they make their own law," Toubel said.

She accused the ruling Islamists of "complicity at least by silence."

Some Tunisian media share her concerns.

"What is serious about all this, more than the activism of these religious extremists, which grows by the day, is the laxity of the authorities who given in every time when faced with the diktats of some bearded fanatics," said the online publication Kapitalis, which is strongly critical of the government.

The ministry of the interior, contacted by AFP, declined to comment on the accusations, saying a statement was being prepared.

But the ministry of culture responded to the forced cancellation of Lotfi Abdelli's stand-up comedy show by accusing those responsible for an "attack on freedom of expression and a dangerous threat to cultural rights."

It failed to explain why the security forces failed to intervene, as Abdelli claimed, but said legal action would be taken, without elaborating.

Ennahda is already under fire from human rights activists for drafting a law, yet to be debated in parliament, that could see anyone convicted of violating sacred values jailed for up to two years.

Many also regard this an attempt to curb freedom of expression and creativity, while the opposition and civil society groups have repeatedly criticised the government for failing to restrain the Salafists.

Ennahda's leader Rachid Ghannouchi said in June that dialogue rather than repression was necessary to avoid the "oppression, torture and imprisonment" characteristic of the former regime of Zine El Abidine Ben Ali, when the Islamists were banned.

But since Ben Ali was ousted in last year's mass uprising, the hardline Islamists have grown increasingly assertive.

A few days after Ghannouchi's comments, suspected Salafists sneaked into a gallery in Tunis and destroyed some works of art they considered offensive to Islam, triggering riots that left one person dead and more than 100 injured.