Indonesian sharia police are "morally rehabilitating" more than 60 young punk rock fans in Aceh province on Sumatra island, saying the youths are tarnishing the province's image.

Since being arrested at a punk rock concert in the provincial capital Banda Aceh on Saturday night, 59 male and five female punk rock fans have been forced to have their hair cut, bathe in a lake, change clothes and pray.

"We feared that the Islamic sharia law implemented in this province will be tainted by their activities," Banda Aceh deputy mayor Illiza Sa'aduddin Djamal, who ordered the arrests, said.

"We hope that by sending them to rehabilitation they will eventually repent."

Hundreds of Indonesian punk fans came from around the country to attend the concert, organised to raise money for orphans.

Police stormed the venue and arrested fans sporting mohawks, tattoos, tight jeans and chains, who were on Tuesday taken to a nearby town to undergo a 10-day moral rehabilitation camp run by police.

A girl cried as women in headscarves cut her long unruly hair into a short bob, and some of the men groaned as their heads were shaved.

"Why did they arrest us? They haven't given us any reason," said Fauzal, 20.

"We didn't steal anything, we weren't bothering anyone. It's our right to go to a concert."

A 22-year-old man from Medan city who did not want to be named said he feared he would lose his job for staying at the camp for 10 days.

"I've just started with a bank in Medan. I don't even know what to tell them because I don't know why I've been arrested."

'Deviant behaviour'

Police said the objective was to deter the youths from "deviant" behaviour.

"They never showered, they lived on the street, never performed religious prayers," said Aceh police chief Iskandar Hasan.

"We need to fix them so they will behave properly and morally. They need harsh treatment to change their mental behaviour."

A local rights activist, Evi Narti Zain, said the arrests breached human rights.

"What the police have done is totally bizarre. Being a punk is just a lifestyle. They exist all over the world and they don't break any rules or harm other people," she said.

Mr Hasan denied the accusation, claiming the rehabilitation program was merely an "orientation into normal Indonesian society".

Aceh, on the northern-most tip of Sumatra island, adopted partial sharia law in 2001 as part of a special autonomy package aimed at quelling separatist sentiment.

Only Muslims can be charged under sharia law, although the non-Muslim community is expected to follow some laws out of respect.

Nearly 90 per cent of Indonesia's 240 million people are Muslims, but the vast majority practise a moderate form of Islam.

Detained Indonesian punks bathe in a lake after having their heads shaved under sharia law in Aceh. ( AFP: Chaideer Mahyuddin )

AFP