Jakarta - Indonesia must crack down on forest clearing after tigers killed six people in less than a month on Sumatra island, the global conservation group World Wide Fund for Nature (WWF) said on Wednesday.

Three people were mauled to death by Sumatran tigers over the weekend, bringing to six the number of people to have been killed in Jambi province by the endangered beasts since late January, officials said.

The head of the provincial conservation agency, Didy Wurjanto, blamed the destruction of the tigers' habitat by illegal logging and palm oil plantations for the attacks on humans.

He said most of the victims were workers at illegal logging camps.

In an unrelated incident, two farmers in Sumatra's Riau province were hospitalized after being attacked by a tiger last weekend, the WWF said.

"As people encroach into tiger habitat, it's creating a crisis situation and further threatening this critically endangered subspecies," Ian Kosasih, director of WWF's forest programme, said in a statement.

"In light of these killings, officials have got to make public safety a top concern and put a stop to illegal clearance of forests in Sumatra," he said.

The statement said clearing of forests by individuals and companies for palm oil and pulpwood plantations was "rampant" in the region.

The loss of the tigers' habitat has lead to a human-tiger conflict, the group said.

The WWF said about 12 million hectares of Sumatran forest had been cleared in the past 22 years, a loss of nearly 50 per cent island-wide.

A female tiger suspected to have killed the four previous victims was caught earlier this month and is currently being kept at a local zoo.

The WWF estimates that there are fewer than 400 Sumatran tigers in the wild and they can only be found on Sumatra.

It said tigers were once widespread on the Indonesian islands of Bali and Java but those two subspecies became extinct in the 20th century. (dpa)