The choking smog has blanketed the capital Kuala Lumpur and other parts of peninsular Malaysia for more than week, disrupting airports and shipping, angering citizens and raising fears over public health.

"I now declare a state of emergency for the whole area of Kuala Selangor and Port Klang with immediate effect indefinitely," Prime Minister Abdullah Ahmad Badawi said in a statement.

Under the measures all workplaces are to remain closed except for essential services, food shops and supermarkets. Schools are to close and citizens are advised to stay at home if possible.

Abdullah acted after the air pollution index (API) reached 529 in Port Klang, a major shipping centre, and 531 in Kuala Selangor. An API above 300 is considered hazardous and 500 triggers a state of emergency.

In Kuala Lumpur the index reached 321, shrouding the city in a yellowish mist and making the tops of buildings disappear.

The prime minister said he hoped no other areas would hit the 500 mark but if they did they would automatically be declared to be under a state of emergency.

The opposition Democratic Action Party said Malaysians were "furious and worried" about the pollution and that it would mount a protest at the Indonesian embassy on Friday.

"As the source of haze is in Sumatra, Malaysians are powerless to do anything to fight this threat to their and our children's health and safety unless Indonesia is serious about taking action," said its leader Lim Kit Siang.

But Foreign Minister Syed Hamid Albar indicated Malaysia would not take a confrontational approach that could damage their fragile bilateral relationship.

"In the interests of neighbourly relations, we must sit down and discuss and consult. This is the common interest," he said.

"We have no other alternative, we cannot go into an open conflict, that will not be good for the region. That will not be good in terms of our relationship," he said at a press conference.

Abdullah said he had suggested asking mosques in mainly Muslim Malaysia to conduct prayers for rain. "Other races and religions could also pray for rain in their own way," he told reporters.

He also said he had called Indonesia's President Susilo Bambang Yudhoyono to offer assistance including cloud-seeding and drafting in firefighters to douse the hundreds of fires on Sumatra island.

"But it is up to them if they are ready to accept our help," he said.

Abdullah also said that Forestries Minister Peter Chin would visit Malaysian-owned palm oil and rubber plantations on Sumatra which are said to be responsible for some of the open burning, and call on them to stop.

More than 700 schools in Kuala Lumpur and surrounding districts were ordered to close until Monday because of the worsening haze, which is causing a rise in asthma attacks and respiratory conditions.

Kuala Lumpur's second airport at Subang was shut Wednesday as visibility sank to less than 300 metres (990 feet) and contingency plans have been made in case the country's main airport has to shut.

For the second day in a row, shipping operations at Port Klang were temporarily suspended as operators decided it was too dangerous to work in the murky conditions.

Meteorology department senior forecaster Kamil Ibrahim said the haze was expected to persist for the next few days, but that there could be a brief respite next week as the winds coming from Sumatra shifted.

However, Indonesian officials warned that the blazes would worsen in coming weeks.

Malaysians, who experienced an even worse haze crisis in 1997 and 1998, were generally calm amid the crisis but some demanded more action.

"We're just wondering what's happening in terms of government-to-government arrangements," said 37-year-old businessman David Shan.

"What our government is doing in terms of addressing the problems coming our of Sumatra -- that's a big concern," he said.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.