(AFP) Scores of policemen are searching for a German student and his local guide who have been missing in Sabah for days, police said today.

The student, identified as Arnie Cornelius from Bremen, and his local guide Joseph Mohamad Faisal - both 21 - were last seen Thursday in a forest conservation park in the state, police said.

They had been researching proboscis monkeys in the 300-hectare swampy Labuk Bay Proboscis Monkey Sanctuary.

The park management reported the men missing late Friday.

The sanctuary is located some 30km from Sandakan, which is on the east coast of Sabah.

Aerial search

"The police air wing has deployed a helicopter to conduct an aerial search," said Hashim Mohamad Yusof, the district police chief heading the round-the-clock search.

Scores of policemen, tracker dogs and sanctuary workers have been scouring the swampy forest for the missing men since Friday, he said.

Rescue teams were also searching the Semawang River, which passes through the sanctuary, he said.

The men were last seen entering the sanctuary early Thursday and were supposed leave it the same day, park officials said.

In Sarawak, Swiss environmental activist Bruno Manser has been missing for 15 months. His family and friends believe he may have perished.

Manser, a staunch defender of the nomadic Penan tribe and the rainforest in Sarawak, travelled to the state on May 23 last year. He has had not been heard from since he sent a letter to his Swiss girlfriend dated May 25.

On August 15, a family of three German tourists went missing in the Cameron Highlands in Pahang but they were found 24 hours later.

On August 16, a 17-year-old British tourist went missing on Mount Kinabalu in Sabah. Searchers found her body a week later. She died of hypothermia.