Indonesia has banned sex outside of marriage in a series of sweeping changes to its criminal code.

The laws, which were ratified on Tuesday, mean that people caught engaging in sexual intercourse or living together outside of marriage may face up to one year in prison.

The changes are part of a legal overhaul that critics say could wind back hard-won democratic freedoms and police morality in the South-East Asian nation.

But legislators hailed the passage of the criminal code that the South-East Asian nation has discussed revising since declaring independence from the Dutch.

“The old code belongs to Dutch heritage … and is no longer relevant now,” Bambang Wuryanto, head of the parliamentary commission in charge of revising the code told lawmakers.

The articles penalising sex outside marriage are among the most controversial revisions. Other contentious measures passed on Tuesday include bans on insulting the president, and expressing views counter to the national ideology, known as the Pancasila.

The revision of Indonesia’s penal code has sparked mass protests in recent years, although the response has been considerably more muted this year.

Parliament had planned to ratify a draft new code in September 2019, but nationwide demonstrations over perceived threats to civil liberties halted its passage.

Tuesday’s approval came even as business groups warned it could harm Indonesia’s image as a tourism and investment destination.

In 2019, the plan sparked alarm on the holiday island of Bali, amid fears that unmarried tourists – including Australians – could face jail for having sex.

At the time, the Bali Hotels Association urged tourists to “stay calm and continue their activities (or planned activities) as usual”. Since then, Bali has been hit particularly hard by the pandemic, and is still struggling to recover.

Prior to the pandemic, Australians accounted for about one in four overseas visitors to Bali.

Since 2019, legislators in the world’s third-largest democracy have watered down some of the articles deemed most contentious.

Revised articles on sex outside marriage and cohabitation, for example, now state such complaints can only be reported by close relatives such as a spouse, parent or child, while insulting the president can only be reported by the president.

But legal experts and civil society groups say the changes don’t go far enough.

“This criminal code is a huge setback for Indonesia,” said Bivitri Susanti, a law expert from the University of Indonesia.

“The state cannot manage morality,” she said. “The government’s duty is not as an umpire between conservative and liberal Indonesia.”

Articles on customary law, blasphemy, protesting without notification and expressing views divergent from the Pancasila were all legally problematic because they could be widely interpreted, she said.

Once ratified, the new code will come into effect after three years as the government and related institutions draft related implementing regulations.

Religious conservatism has been on the rise in Indonesia, the world’s largest Muslim-majority nation, in recent years. Legal experts suggest the new laws around morality and a separate article on customary law will reinforce discriminatory and sharia-inspired bylaws at the local level.

Opponents of the bill have highlighted articles they say are socially regressive, will curb free speech and represent a “huge setback” in ensuring the retention of democratic freedoms after the fall of authoritarian leader Suharto in 1998.

-with AAP