Rain and favourable winds have brought clear skies to vast areas of Southeast Asia stricken for weeks by hazardous smoke from Indonesian fires, with officials expressing hope Thursday that the crisis could end soon.

Parts of Indonesia, Malaysia, and Singapore enjoyed the cleanest air in weeks, while affected areas of the Philippines and Thailand also have seen an end to pollution that has sickened tens of thousands and caused flight cancellations and school closures.

Malaysia's top weather forecaster went so far as to declare that the region's rainy season was beginning.

Some experts have previously warned the El Nino weather phenomenon could delay the rains for months, prolonging the environmental disaster.

"The northeast monsoon has arrived. It is the raining season for Malaysia," said Che Gayah Ismail, director-general of the country's Meteorological Department.

"We should have blue skies and no more haze because the northeast monsoon winds will blow the haze from Indonesia's forest fires into the Indian Ocean," she told AFP.

Indonesian authorities were more guarded, but also said further rains were expected.

Recent rainfall on the huge islands of Sumatra and Borneo -- where hundreds of forest and agricultural fires have smouldered for weeks -- have helped reduce the smoke clouds, said Indonesia's disaster agency spokesman Sutopo Purwo Nugroho.

- Rains 'welcomed with joy' -

Affected communities "welcomed this with joy and said grace after two months of being held captive to haze", Sutopo said in a statement.

The rains there included both natural precipitation and artificially induced showers from cloud-seeding, he added.

Indonesia's national weather agency has forecast more rain, which will allow for more cloud-seeding activities, Sutopo said.

The fires and the resulting haze occur to varying degrees annually during the dry season as land is illegally cleared by burning, stoking tensions between Indonesia and its smog-hit neighbours Malaysia and Singapore.

But experts had warned this year's outbreak was on track to become the worst yet, exacerbated by El Nino's bone-dry conditions.

The US-based World Resources Institute said earlier this month that the fires were spewing more greenhouse gases into the atmosphere each day than the United States, the world's second-largest emitter of the gases blamed for global warming.

Indonesia this month agreed to accept international help after failing for weeks to douse the fires, and has employed dozens of planes and thousands of personnel on the ground.

But the fires are typically only brought fully under control in November with the onset of the rainy season.

While noting that the weather changes had helped, Singapore's National Environment Agency (NEA) said that air quality in the city-state could still suffer if winds were to change.

southern areas of the Philippines have been aided by the departure of Typhoon Koppu last week, authorities said. The typhoon had triggered winds that pulled the haze toward the country.

"The Philippines is now haze-free," Philippine weather bureau forecaster Aldczar Aurelio told AFP.

But he added that further typhoons -- three more are expected to hit the country this year -- could draw the Indonesian haze back.