At least six people died and 200 were injured as supporters of an unsuccessful presidential candidate clashed with security forces in the Indonesian capital on Wednesday.

Protesters burned vehicles and threw rocks at police, who responded with tear gas and rubber bullets in a bid to quell the unrest.

The protesters tried to force their way into the downtown offices of the election supervisory agency late on Tuesday and clashes have continued since then.

"As per 9 o'clock this morning, there were 200 people hurt being brought to five hospitals," Jakarta's governor, Anies Baswedan, told broadcaster TVOne.

"The number of people dead was six," he said, adding that hospitals were conducting post mortems to determine the cause of death.