Lawyers and rights activist are demanding Sri Lanka's chief justice resign because he is being investigated for involvement in an alleged coup plot soon after this month's presidential election.

Hundreds of protesters outside the Supreme Court on Wednesday accused Mohan Peiris of undermining the judiciary's independence and integrity by being partial to ousted President Mahinda Rajapaksa.

Police have questioned Peiris over his presence at Rajapaksa's official residence when results of the Jan. 8 election were being announced. The new government has complained that Rajapaksa had discussed with military, police and legal officials ways he could illegally stay in power when early voting results indicated he was losing.

Peiris was a Rajapaksa aide installed as chief justice after the then-government impeached the incumbent.