Thousands of Indonesian firefighters have been deployed to battle raging land and forest fires, as the number of hot spots rises because of the dry season.

Big palm oil and pulp-and-paper firms, which had been partly blamed for last year's regional haze crisis, are also joining the military, police and other government agencies to douse the flames, Peatland Restoration Agency (BRG) chief Nazir Foead told The Straits Times yesterday.

"So far we see that the big companies are performing much better than last year. They are very responsive in cooperating with the authorities to put out forest fires even not on their concessions," he said, but declined to name the firms.

The companies have sent their own personnel to fight fires as well as help to detect and alert the authorities of potential fires, among other things, he said.

"Everyone has fully realised it is a major priority for the government, and also aware of the consequences if things do not improve, for businesses, and administrative plus legal consequences," he added.

Errant companies, mostly palm oil and pulp-and-paper firms, had been fingered in last year's haze crisis which affected millions of people across South-east Asia and caused severe respiratory illnesses and deaths. The crisis brought Indonesia to the brink of a national emergency and led to the boycott of products made by the firms believed to be behind the fires.

The Indonesian authorities have been implementing measures to ensure there is no repeat of the haze this year, including taking firms to court. Last Thursday, a sago plantation company was fined a record 1.07 trillion rupiah (S$110 million) for causing fires that spread uncontrollably last year - the biggest fine imposed on a plantation business.

Meanwhile, soaring temperatures have contributed to an increase in the number of hot spots this week, with 482 detected by satellites on Tuesday evening.

But the figure dropped to 153 hot spots yesterday evening, including 17 in Riau province, according to the country's National Disaster Management Agency.

But the government remains on alert to ensure the situation is under control, agency spokesman Sutopo Purwo Nugroho told The Straits Times yesterday.

"The number of hot spots is always fluctuating. The peak of the dry season is September," he said, adding that the figure "is still much lower this year", compared with last year. More than 22,000 personnel had been sent to the hard-hit provinces of Riau, Jambi and South Sumatra, he said.

Eleven aircraft had also been deployed to carry out waterbombing and cloudseeding, and four more were being prepared to be sent to Jambi and West Kalimantan, he added.

Mr Nazir said BRG last Friday began to expand its project to build deep wells in five more provinces, after the technique was "proven effective" on pilot sites in the provinces of Riau and Central Kalimantan.

The deep wells have helped to keep the ground moist, preventing peat fires from spreading.

"There was no fire in the village which has been equipped with the wells," Mr Nazir said, adding that at least 6,000 deep wells will be built in fire-prone peatland areas by the end of this year to anticipate next year's dry season.

He added: "We are all working together to restore our peatland ecosystems very seriously, and to prevent peat fires."