Bersih 2.0, a coalition of nongovernmental organisations, said it would not abandon its campaign, with Prime Minister Najib Razak widely expected to call elections by early next year.

The opposition says voting favours the Barisan Nasional coalition, who have ruled Malaysia for half a century but saw their majority slashed in the previous general election, in 2008.

"The work for Bersih 2.0 continues. We believe that the best way forward is for the setting-up of a royal commission of inquiry. We have asked for that," Bersih head Ambiga Sreenevasan told reporters.

"The idea is for them to look at the entire electoral system, look at an overhaul of the system... It's clearly the wish of the people that we move forward with the agenda for electoral reform," she said.

She added the commission should consist of experts "acceptable to the people" to study Bersih's demands, such as allowing Malaysians abroad to vote and introducing indelible ink to prevent voters from casting multiple ballots.

Backed by opposition parties, Bersih mobilised tens of thousands of people to take the streets in the capital Kuala Lumpur on Saturday in the country's biggest rally in four years.

Police, which had declared the protest illegal, used tear gas and water cannon and arrested more than 1,600 people.

Before the protest, the Election Commission, which is in charge of running all polls, announced it would fingerprint voters using a biometric system to address activists' concerns of people voting more than once.

But few details were given and it is still unclear how this could be implemented.