Police in Bangkok on Sunday fired water cannon, rubber bullets and tear gas at protesters demanding that Prime Minister Prayut Chan-o-cha step down and the government be held accountable for its mismanagement of the Covid-19 pandemic.

The demonstrators clashed with police after some tried to dismantle barricades set up across Ratchadamoneon Nok Avenue in a bid to prevent them from marching to Government House.

A number of people were injured, and an area near Democracy Monument was set up for health volunteers to help protesters injured during the police onslaught.

"Murderous government!," Panusaya "Rung" Sithijirawattanakul, a protest leader, tweeted after the use of force.

The marchers got as far as Nang Loeng intersection, where they displayed mock body bags and burned effigies of the prime minister.

At around 6.30pm, the Free Youth movement announced the end of the rally.

Earlier, cars and motorcycles joined demonstrators walking from Democracy Monument to Government House. Led by the Free Youth movement, the anti-government protesters were defying a ban on public gatherings.

Demonstrations began early last year by calling for the ouster of Prayut and the restoration of democracy, but have recently added the government's mismanagement of the coronavirus pandemic to their agendas.

"The government has been poor at managing the situation and if we don't do anything there will be no change," one protester said.

The mock body bags symbolised the government's failure to curb the spread of the virus that has led to 3,341 deaths since the outbreak began early last year.

More than 2,000 police were deployed to counter the rally.