Haze crisis engulfed parts of the busy Malacca Strait and the major port of Klang today, reducing visibility to 200 metres and forcing one port operator to shut down.

The government said Port Klang, west of the capital Kuala Lumpur and fronting onto the strait, had registered an alarmingly high air pollution index of 410.

Several other parts of the country hit by the haze, caused by forest fires in Indonesia's Sumatra province, also recorded levels in excess of 300 which is considered officially "hazardous".

Northport, one of three port facilities at Port Klang, suspended its operations late today due to the poor conditions, the official Bernama news agency said.

Its deputy chief executive officer Mohd Haris AbAziz said it would keep reviewing the situation and resume business once the situation improved.

Northport official Quake Kuan Hock said earlier that visibility had plummeted to just 200 metres and the situation was worsening, leaving workers struggling in night-like conditions.

Quake said all the port vehicles were forced to put on their headlights and sound their horns to avoid collisions. Workers had been given face masks and preparations had been made in case any employees fell ill.

"We have an in-house clinic which has been put on standby in case any of the workers are asthmatic and we have our own in-house ambulances, and they are all on standby," he said.

Westport, another major facility, said its staff were being rotated every three hours to minimise outdoor exposure.

The Star daily said a container ship ran aground in the murky conditions, and the meteorological department warned that the haze posed a hazard for ships without navigational equipment.

Piracy threats

Gopal Krishnan, president of the Port Klang Shipping Agencies Association, called on the government to ensure safety in the area.

"We are a bit worried and the government has to take some action to ensure the haze is gone in order for the ships to berth and unberth safely," he said.

Noel Choong, head of the International Maritime Bureau's Piracy Reporting Centre, said reduced visibility and unhealthy outdoor conditions would make it more difficult to ensure security in the piracy-prone Malacca Strait.

"Normally the crew do anti-piracy watches by walking around the ship. With these conditions it's not that simple. If you keep the watch just to the bridge, you may miss them if they come around the stern or another side," he said.

"By the time the crew spots them it's a bit too late and so it's difficult to keep anti-piracy watches," he said.

In 1997 and 1998 choking haze caused mainly by Indonesian forest fires enveloped parts of Southeast Asia including Malaysia for months, causing an estimated 9.3 billion dollars in economic losses to the region.