Singapore’s parliament has passed a law aimed at preventing foreign interference in domestic politics, which the opposition and activists have criticized as a tool to crush dissent.

The law, approved after a marathon session that stretched to near midnight on Monday, would allow authorities to compel internet service providers and social media platforms to provide user information, block content and remove applications used to spread content they deem hostile.

Groups and individuals involved in local politics can be designated as “politically significant persons”, which would require them to disclose foreign funding sources and subject them to other “countermeasures” to reduce the risk of overseas meddling.

Violators risk prison terms and hefty fines on conviction.

Campaigners say it is the latest piece of draconian legislation to be rolled out in a city-state where authorities are frequently accused of curbing civil liberties.

But in a lengthy address to parliament, law and home affairs minister K Shanmugam said Singapore was vulnerable to “hostile information campaigns” carried out from overseas and through local proxies.

“The internet has created a powerful new medium for subversion,” he said.

“Countries are actively developing attack and defense capabilities as an arm of warfare, equal to, and more potent than, the land, air and naval forces.”

His People’s Action Party, which has governed Singapore for more than six decades, stamped its parliamentary majority to push for the bill’s passage with 75 “yes” votes. There were 11 “no” votes and two abstentions.

The main opposition Workers’ Party had called for changes to be made to the draft bill, raising concerns about its broad provisions, while another opposition group called for further consultations.

Phil Robertson, deputy Asia director for Human Rights Watch, said Singapore used foreign influence as a “bogeyman to justify their expanded persecution of opposition politicians, civil society activists and independent media”.

Singapore’s international reputation “will take the hardest knock” from the new law, he said.

Media watchdog Reporters Without Borders (RSF) has warned the bill carries “the seeds of the worst totalitarian leanings”.

“This bill institutionalizes the persecution of any domestic entity that does not toe the line set by the government and ruling party, starting with independent media outlets,” Daniel Bastard, the head of RSF’s Asia-Pacific desk, said.

He also warned there was a “lack of independent legal recourse for those who are given orders by the government” – although Shanmugam insisted the bill provided for adequate judicial review.

Independent media have faced increasing pressure in the city-state, with leading news website the Online Citizen suspended last month for failing to declare its funding sources. Mainstream media is mostly pro-government.

The bill comes two years after the introduction of a law aimed at combatting online misinformation that was criticized by rights groups and tech giants for curbing free speech.