Kuala Lumpur – Haze has persisted over parts of Malaysia due to smoke from forest fires in Indonesia but there are hopes of rain to clear the air, an official said.

Parts of the northern resort island of Penang, and Perak, Selangor and Kedah states were suffering poor visibility from smoke particles being blown from Indonesia's Sumatra island by southwesterly winds.

"There are more hotspots in Sumatra. The southwesterly winds are blowing the burning particles to Malaysia," an official with the meteorological services department told AFP.

But the official said some rain was expected later Wednesday which may bring some respite. "Hopefully, it will reduce the haze," she said on condition of anonymity.

The Department of Environment failed to release the country's daily air quality index at the scheduled time due to what was described as a technical problem.

But among the worst affected areas with visibility at five kilometres (three miles) or less were Bayan Lepas and Butterworth in Penang, Sitiawan in Perak and Langkawi in Kedah, the official said.

On Tuesday air quality in parts of Malaysia, including the major shipping centre of Port Klang west of the capital, plunged to unhealthy levels.

Meteorological authorities said the first haze seen this year, which is also affecting southern Thailand, could sweep over the Malay peninsula as it did in 2005.

Burning in Indonesia and some parts of Malaysia to clear land for crops causes an annual haze that afflicts countries in the region, including Singapore and Thailand.

Last August a state of emergency was declared in Port Klang and another town on Malaysia's west coast as pollution soared to extremely hazardous levels.