Jakarta – Fires which have resumed in Indonesia's Sumatra and Kalimantan regions have ravaged at least 5,561 hectares of forest and scrub in the past month, a report said Saturday.

The National Environmental Impact Management Agency said fires in Sumatra's Riau province alone had caused losses of 8.9 billion rupiah (1.2 million dollars) since July, the Antara news agency reported.

The widespread burning, blamed on smallholding farmers and plantation owners, has revived fears of haze blanketing neighbouring countries in a repetition of a regional environmental disaster two years ago.

The agency defined the cost estimate from the Riau fires in terms of lost income from the forestry sector and the need for funds to replace trees.

It excluded in its estimate economic losses caused by poor visibility sparked by the haze and increased costs for the resulting health care.

It said that smoke from the fires had caused a rise in the incidence of respiratory illnesses and disruption of school education.

Riau authorities last month called for the closure of schools especially at nursery and primary levels, saying that youngsters were most vulnerable to the effects of the smog. They have also called on schools to refrain from conducting outdoor activities for their older pupils.

Forest fires have reappeared in the lower half of Sumatra island and several parts of Kalimantan, the Indonesian part of Borneo island, since June.

But occasional rain has stopped the haze from reaching the levels it hit in 1997, when huge forest and ground fires during a prolonged drought destroyed more than 10 million hectares of Indonesian forest.

The meteorology office here said that in the past week visibility in Riau and other southern Sumatran provinces had been good owing to heavy rainfall.

In 1997 and early 1998, the smoke haze covered a wide swathe of skies over Indonesia and neighbouring countries, causing massive economic losses along with serious health problems and visibility hazards to ships and planes.

On Thursday a meeting in Singapore of environment ministers from the Association of Southeast Asian Nations pressed Indonesia to take urgent action to prevent a renewal of the 1997 crisis. The meeting was brought forward from October because of the urgency of the potential problem.

The ministers urged Indonesia to quickly implement the necessary by-laws and regulations to enforce the "zero-burning" policy imposed by the government of President B.J. Habibie earlier this year. Indonesian officials have cited a lack of funds and personnel for their failure to enforce the policy.