A presenter for a London-based radio service critical of the government of Malaysia's Sarawak state has gone missing, the station and opposition figures said Friday.

Radio Free Sarawak presenter Peter John Jaban was taken away by three men shortly after arriving from Britain on Thursday in Sarawak on the huge island of Borneo, they said.

"We still have not received any update... We are worried for him," Alan Ling, a state lawmaker with the opposition Democratic People's Party, told AFP.

Radio Free Sarawak broadcasts for two hours daily in reports targeted at Sarawak's large tribal communities.

The reports typically focus on alleged graft by the state government in the harvesting of the state's rich rainforest timber resources.

The service was founded by Clare Rewcastle Brown, the sister-in-law of former British prime minister Gordon Brown.

Michael Teo, an official with the People's Justice Party led by opposition leader Anwar Ibrahim, said he picked up Jaban, who is from Sarawak, from the airport in the city of Miri.

However, three men later stopped his car and took Jaban away in their vehicle.

Sarawak police chief Acryl Sani Abdullah Sani said authorities were investigating the case but denied police were involved.

"We have never arrested him," he told AFP.

"To say we are worried is an understatement" the radio service's founder Rewcastle Brown was quoted as saying in a news release by the Bruno Manser Fund, a Swiss-based group that also campaigns against alleged timber graft.

She said the service was "desperately trying to find where Peter is".

Critics accuse powerful Sarawak chief minister Abdul Taib Mahmud of systematic corruption and plundering Sarawak's natural resources, harming indigenous tribal groups.

In December, environmental groups and activists from Malaysia, Europe and Australia issued a letter to Malaysian authorities calling for the arrest of Taib and 13 relatives for graft.

Malaysia's Anti-Corruption Commission said last year that it had started a probe into Taib, who has governed Sarawak since 1981.