Denpasar – Thousands of protesters rallied on the Indonesian holiday island of Bali on Saturday to demonstrate against an anti-pornography bill denounced by critics as a threat to national unity.

More than 5,000 protesters surged through the streets of the mostly Hindu island's capital in opposition to the bill under deliberation in Jakarta.

The bill, which looked set to be passed several weeks ago but has been pushed back amid a public outcry, criminalises all public acts and material capable of raising sexual desires or violating "community morality".

Protesters denounced the proposed law as too broad and a threat to local customs on the island, where naked temple statues proliferate and skimpily dressed foreign tourists relax on beaches.

Demonstrators turned up to the rally in traditional Balinese clothes including semi-see-through temple blouses, saying such clothes could be deemed too suggestive if the law was passed.

"The porn bill clearly doesn't accommodate minorities and therefore it shouldn't be passed," student activist I Wayan Suardana said.

The protest took on a carnival atmosphere with western-style music and dancing by Papuan tribesmen wearing only traditional penis sheaths, body paint and headdresses made from leaves.

"If the lawmakers pass the porn bill, they will simply destroy our pluralism. It's a direct threat to our country's unity and it deserves to be gotten rid of for good," student activist I Gusti Agung Jelantik said.

The bill, which is being pushed by Muslim parties in Jakarta, is being challenged on other islands in the archipelago nation, which encompasses cultures ranging from conservative Islam to semi-naked animist tribesmen.

Although it is the world's largest Muslim-majority country, Indonesia has significant and officially recognised minorities of Christians, Hindus, Buddhists and Confucians.