Firemen backed by helicopters fought forest fires covering around 1,000 hectares (2,500 acres) today as smoke drifted over large parts of Malaysia, including the capital Kuala Lumpur.

The air quality in some areas, such as Malacca in the south and Port Klang west of the capital, was "unhealthy", the Department of Environment's air division director Che Asmah Ibrahim told AFP .

Visibility was down to two kilometres at the site of the old international airport at Subang near Kuala Lumpur and around seven kilometres at the new airport south of the capital, according to the Meteorogical Service Department.

Copters water-bomb fires

Firemen were battling bushfires in the central states of Pahang and Selangor and in Kelantan and Perak to the north, said Putrajaya Fire and Rescue Department spokesman Abdul Razak Muda.

Helicopters have been deployed in Selangor and Kelantan to water-bomb the fires, which broke out after a long period of hot, dry weather.

Forest fires in Malaysia were usually started by farmers clearing land for planting crops, Abdul Razak said.

The government would launch cloud-seeding operations if the dry spell continued and the level of water in the main dams fell to critical levels, the Natural Resources and Environment Ministry's parliamentary secretary Sazmi Miah said.