Kuala Lumpur – Haze from forest fires in neighbouring Indonesia blanketed the northern parts of peninsular Malaysia, reducing visibility to as low as three km, a newspaper and residents said on Saturday.

Smoke from forest fires in Sumatra, just across the Straits of Malacca, was expected to affect the states of Penang, Perak and Kedah in the next few days, the Sun reported, adding that the government had urged people to wear masks when necessary.

Penang, where visibility has fallen to three km from the normal 10 km, is the worst affected as southwest wind from the large Indonesian island of Sumatra blows the haze to the peninsula, the paper said.

"The northern states could experience hazy conditions for a few days, depending on the wind direction," Shamsudin Abdul Latif, deputy director-general of the environment ministry, was quoted as saying by the newspaper.

"We detected more than 500 hot spots in northern Indonesia, and more than 900 spots in Kalimantan yesterday," said Shamsudin, referring to Sumatra and the Indonesian side of Borneo island.

Bouts of haze from forest fires, mainly coming from Indonesia's Kalimantan province on Borneo, have been a problem for six weeks, periodically affecting other parts of Southeast Asia. The fires, triggered by both land clearing and slash and burn farmers, create health and environmental problems every year.

In August, choking haze from Sumatra shrouded some states in the western parts of the peninsula and badly affected visibility in capital Kuala Lumpur.

"Penang is still hazy this morning even though it has rained. But I guess the situation is not as bad as early last year when haze from Sumatra also hit this area," a tin trader in Penang said by telephone.

Earlier this year Malaysia banned open burning, even barbecues, with exceptions made for cremations and destroying animal carcasses, following a spate of forest and scrub fires around the country and in Indonesia. Thick haze from major fires on Borneo and Sumatra in 1997 and 1998 spread to Singapore and Malaysia and cost regional economies $9 billion in damage to farming, transport and tourism.

Conservationists have long criticised Jakarta for failing to protect its natural resources. Indonesia admits its laws are too weak to deal with the problem and is promising reform.