The law tightens regulation of social media in the city-state, where rights groups have accused the government of using legislation to stifle free expression.
Social media firms face a fine of up to Sg$1.0 million ($715,000) if they fail to comply.
Singapore passed a law against online falsehoods in 2019, which the government said was aimed at fighting disinformation but which political activists and tech giants criticised as restrictive.
The new law empowers the regulator Infocomm Media Development Authority (IMDA) to issue orders to platforms, which also include Instagram and YouTube, to take down content deemed to be "egregious".
This covers content advocating terrorism, suicide and self-harm, violence, child sexual exploitation and those likely to undermine racial and religious harmony.
As well as fines, the IMDA can also order internet service providers to block access by users in Singapore.
Social media companies had no immediate reaction.
Minister for Communications and Information Josephine Teo told parliament the new law aims to fill gaps not addressed by other legislation.
She cited the case of a 14-year-old girl in Britain who took her life after being exposed to such posts.
"There have also been reports of users' accidental deaths while attempting to mimic videos of impossible physical stunts," Teo said.
Users are now more likely to see such harmful content on social media feeds that are "pushed via algorithms" and become viral within minutes, she said.
"We must have the ability to deal with harmful online content accessible to Singapore users, regardless of where the content is hosted or initiated," Teo said.
This story has been published from a wire agency feed without modifications to the text.
