Malaysian activists and bloggers are staging an online black-out for one day to protest against changes to a law they say restricts free speech online.

They have replaced their home pages with black screens critical of the Evidence Act, revised in April, for Internet Black-out Day.

Critics say the law makes people unfairly liable for content published from networks and personal devices.

Officials deny the change is meant to silence critics ahead of an election.

The revised law means that Malaysians could get into trouble even if their devices or internet connections have been hacked into, critics say.

The Centre for Independent Journalism in Malaysia said the revision was "a bad law passed in haste and does not take into account public interest and participation", said the Agence-France Presse news agency.

Critics want the law to be changed or scrapped completely.

Premesh Chandran, founder of online news site Malaysiakini, said that the burden of proof on internet users was unfair.

"In other words, if defamatory comments are posted on a blog, the blog owner is likely to be sued or charged with criminal defamation, Malaysiakini said in a statement on its website.