Kuala Lumpur - Malaysian police detained an opposition party leader and an anti-government activist for alleged sedition, after they called for a protest against the government.

Wong Chin Huat, an activist with the Coalition for Clean and Fair Elections, on Tuesday urged Malaysians to wear black on Thursday to protest the ruling National Front coalition's takeover of the state of Perak in February.

Wong, a lecturer at the Malaysian campus of Australia's Monash university, was detained at his home late Tuesday under the Sedition Act, a spokesman from the university said Wednesday.

Vice-president of the hardline opposition Parti Islam SeMalaysia (PAS) Mohamad Sabu was also detained Wednesday under the sedition act, for urging members of the public to assemble and protest the opening the Perak state assembly, official Bernama news agency said.

The controversial takeover in Perak was slammed by critics who claim the National Front violated the constitution when it unseated the state's opposition-led government through lawmaker defections.

The detentions also sparked opposition fears of a crackdown on dissent by the nation's newly appointed prime minister.

Malaysian bar association president Ragunath Kesavan said Wednesday the arrests "did not augur well for Prime Minister Najib Tun Razak's promise of openness and respect for the people".

"We reiterate our stand that legislation such as the Sedition Act is an absolute affront to democracy and urge the government to repeal the act," he said in a statement.

Sedition is punishable by up to three years in jail.

Voter confidence in the ruling coalition has dropped to an all-time low, leading to the opposition People's Alliance's major gains in the March general elections last year. (dpa)