Malaysians were advised today to stay indoors while hospitals are on the alert for health problems after air quality was declared unhealthy as a haze cloaked Kuala Lumpur and surrounding areas.

"Try to stay indoors as much as you can," Health Department director-general Ismail Merican told the Bernama news agency.

All government hospitals and clinics have been directed to be on the alert for an increase in respiratory problems, coughs, sore throats and eye irritations, The New Straits Times reported.

Kuala Lumpur and four surrounding areas including the administrative centre Putrajaya were declared unhealthy Wednesday, as well as regions in the neighbouring southern states of Negeri Sembilan and Malacca.

Strenuous activity outside would be unhealthy for most people, especially for those with respiratory problems like asthma and allergies, authorities said.

Improved situation

However, the Department of Environment said the hazy conditions had partially eased on Thursday.

"The situation has improved. The air quality has improved, all of our stations around the country are recording 'good' or moderate' air quality," its deputy-director general Lee Heng Keng told AFP .

The number of fires in Indonesia's Sumatra province, which are blamed for causing the haze along with blazes outside Kuala Lumpur, had also fallen to 134 as of late Wednesday, he said.

Meteorological experts had predicted that the conditions could worsen due to dry weather and strong winds that would intensify the effects of nearly 600 fires in the Indonesian provinces of Riau and northern Sumatra, as well as Indonesia's Kalimantan and Malaysia's Sarawak state.

Peat fires which started Monday in Cyberjaya, south of Kuala Lumpur, have also contributed to the smoky conditions in the capital, blocking out views of the city's skyscrapers and permeating office buildings with the smell of smoke.

Haze caused by fires in Indonesia and Malaysia is a common occurrence during hot, dry seasons.

In 1997 and 1998, choking haze caused mainly by Indonesian forest fires enveloped parts of Southeast Asia including Malaysia for months.

They caused an estimated 9.3 billion dollars in economic losses to the region due to serious health problems, traffic hazards and flight disruptions.