Smoke from the fires is causing haze that is drifting across neighbouring Malaysia, where authorities said on Sunday air quality and visibility in some areas had fallen from 'good' to 'moderate' over the previous week.

Most of the illegal fires were the result of land and forest clearing for traditional farming and palm oil plantations, forestry ministry official Israr Albar said.

'The number of hotspots may increase two to three-fold this month. The farmers are clearing land for cultivation in more areas,' he said.

'Land cleared by local residents accounted for 65 to 70 percent of the fires.' There were 401 hotspots in Riau this month compared to 227 in the whole of June last year, he said.

Almost 1,000 hotspots were detected in Riau, 73 in West Kalimantan and 18 in Central Kalimantan last month, the start of the dry season.

Agricultural burning during the dry season, which ends around September, is an annual source of smoky haze that affects tourism and contributes to health problems across the region.

The government has outlawed land-clearing by fire but weak enforcement means the ban is largely ignored.

Environment ministers from Singapore, Malaysia and other regional nations have urged Indonesia to promptly ratify a regional treaty aimed at preventing cross-border haze pollution. -- AFP

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