An Indonesian human rights group on Friday condemned the use of caning in staunchly Islamic Aceh province, saying the punishment violated the country's constitution.

The Commission for Missing Persons and Victims of Violence (Kontras) urged the government to repeal a bylaw used by the partially autonomous province to carry out the punishment under Muslim sharia law. Dozens of men have been publicly caned there for gambling this month.

Kontras said that caning should be barred by clauses in the country's constitution which grant citizens freedom from torture and from acts that detract from human dignity.

"The Indonesian government has to review the use of caning as punishment," deputy coordinator Indria Fernida said in a statement. "A slow response by the government will indicate that they neglect this matter and adhere to a kind of punishment that violates the constitution and human rights principles," she said.

On Thursday, 19 people were being lashed in public after being caught gambling. Twenty – one people were also lashed earlier this month for gambling, while the punishment is also used for offenses including adultery.

Sixteen people were reportedly caned in Aceh last year, according to rights group Amnesty International, which said last week that the punishment violated the UN Convention against Torture.

"It seems that Aceh's authorities are increasingly resorting to public caning in violation of international law," Amnesty's Asia – Pacific director Sam Zarifi said.

Aceh, on the northern tip of Sumatra island, adopted partial sharia law in 2001 as part of an autonomy package aimed at quelling separatist sentiment. Caning carried out there is mainly aimed at causing shame rather than injury.