Human rights watchdog Amnesty International has joined the chorus of condemnation against Aceh province's passing of a new Islamic law calling for adulterers to be stoned to death and homosexuality and premarital sex to be punished by lashes.

In a statement released on Thursday, the organization called for the law to be repealed immediately.

"The new criminal bylaw flies in the face of international human rights law as well as provisions of the Indonesian constitution," said Sam Zarifi, Amnesty International's Asia-Pacific director, in a statement.

"Stoning to death is particularly cruel and constitutes torture, which is absolutely forbidden under all circumstances in international law," he added.

The bylaw, locally called Qanun Jinayah, replaces elements of the Criminal Code with Shariah, or Islamic, law for Muslims.

The bylaw mandates that residents of Aceh could receive 100 lashes for engaging in sex out of wedlock, up to 400 lashes for child rape, 100 lashes for homosexual acts and 60 lashes for gambling. If found guilty, adulterers could be stoned to death.

"We welcome the concerns expressed by different levels of the Indonesian government about these laws," Zarifi said. "But the proof is in the doing, and as long as these laws stay on the books they pose a serious threat to Indonesia's international human rights obligations."

Some of these provisions, particularly punishment by caning, are not new in Aceh and already violate international human rights standards on cruel, inhuman and degrading treatment, the statement said.

Amnesty International urged Aceh's newly elected legislature, due to take office in October, to repeal the law as matter of urgent priority and called on the legislature to ensure all local regulations in Aceh fully conform with international human rights law and standards.

The Indonesian government should ensure that the decentralization process and regional autonomy does not come at the expense of human rights, the statement added.