The parliament dominated by lawmakers from President Abdulla Yameen's Progressive Party of Maldives voted 47 to 31 in favour of the controversial bill that criminalises defamation.
Local rights activists say the law allows the government to impose severe penalties on those seeking to exercise freedom of speech, including shutting down news organisations and jailing journalists for up to six months.
"This is truly the end of free media in the Maldives. The government no longer needs an excuse to shut down media outlets or crack down on dissenters," Ali Naafiz, assistant editor of the private Mihaaru news website, told AFP.
Yameen has resisted the international pressure, saying Western governments already have similar laws.
UN rights official Mona Rishmawi, speaking in Geneva, described the law as "very, very, very wide". It could target journalists and human rights defenders and risks "crippling freedom of expression", Rishmawi said.
Police arrested 16 journalists in April for protesting against the bill in the Maldives, most of whose political dissidents are already in jail or in exile.
But it has been gripped by turmoil since its first democratically-elected leader Mohamed Nasheed was toppled in 2012.
Nasheed, whose jailing last year on terror charges has been widely criticised by the West, has since secured political asylum in Britain after travelling there for medical treatment while on prison leave.
