Two Indonesians are to go on trial in an Islamic court for having gay sex and could receive 100 strokes of the cane if found guilty, officials in the conservative province of Aceh said, sparking calls from a rights group for their release.

Aceh is the only province in Muslim-majority Indonesia that criminalises same-sex relations and that uses sharia as its legal code in addition to the national criminal code.

"The case has been sent to the sharia court of Aceh... It involves sodomy which can be punished by 100 lashes," Tarmizi, head of investigations with Aceh's religious police, said on Monday.

Human Rights Watch (HRW) called on Indonesia to release the men who were detained last month after vigilantes reported them to religious police for allegedly engaging in gay sex.

"These men had their privacy invaded in a frightening and humiliating manner and now face public torture for the 'crime' of their alleged sexual orientation," HRW's Phelim Kine said in a statement.

"Indonesian authorities should immediately and unconditionally release the two men."

In 2014, Aceh enacted a law that punishes anybody caught engaging in consensual gay sex with 100 lashes, 100 months in jail or a fine of 1,000 grams of gold.

It also sets out punishment for sex crimes, unmarried people engaging in displays of affection, adulterous relationships and underage sex.

Authorities in the province on the northern tip of Sumatra island caned 339 people in 2016 for a range of crimes, according to HRW.

Religious police in Aceh have also been known to target Muslim women without head scarves or those wearing tight clothes, and people drinking alcohol or gambling.

Two women were detained in October last year on suspicion of being lesbians after they were seen hugging in public, and were made to undergo "rehabilitation", according to media reports.

The lesbian, gay, bisexual and transgender (LGBT) community has faced growing pressure since high-ranking government officials last year expressed reservations about activism by its members.