“Web sites now provide Malaysian content by Malaysians for Malaysians for those who have access to the Internet,” said Jahabar Sadiq, editor of The Malaysian Insider, a news Web site established in 2008.

Such sites have made it increasingly difficult for the government to control the narrative in this country, where one party has dominated national politics since independence from Britain more than 50 years ago. And they are intensifying the pressure on politicians to be more accountable.

“They have lost the monopoly on truth,” said Steven Gan, editor in chief of Malaysiakini. “For a long time, the government had complete control over the news agenda through the control of the mainstream media. That is gone. They can continue to tell the mainstream media what to report, but that doesn’t stop Malaysians from knowing that there’s another version of the truth out there, and they get it from the Internet.”

The number of Internet users in Malaysia, which has a population of 28 million, has grown from 3.7 million in 2000 to 16.1 million last year, according to The Economist Intelligence Unit. Numerous Web sites offering news and analyses have sprung up in recent years; the country is home to a vibrant community of bloggers; and social media sites like Twitter and Facebook are immensely popular.

Media freedom advocates have long complained that the laws governing newspapers and televisions stations have stifled political debate and fostered a culture of self-censorship among mainstream journalists. The print media are regulated by the Printing Presses and Publications Act, which requires most newspapers to renew their licenses annually. But the 1998 Communications and Multimedia Act — which governs cyberspace — contains no such requirement.

“I think they’ve managed to challenge the authoritative ways in which news is defined and formed in Malaysia,” Masjaliza Hamzah, executive officer of the Kuala Lumpur-based Center for Independent Journalism, said of the local news Web sites. She added that the sites often cover issues like human rights, which does not “get the coverage that it deserves” in the print media.

After Mr. Najib announced the need to review the media laws, the home affairs minister, Hishammuddin Hussein, said that the government would review the Printing Presses and Publications Act. However, he also said that “in a multiracial and multireligious society, filtering must be done, as absolute freedom can cause chaos,” according to a report by The Malaysian Insider.