KUALA LUMPUR, July 17 — Southeast Asia’s environment ministers pledged today to lobby their governments to fully share data that includes concession maps in a bid to make accountable the companies suspected of being behind slash-and-burn farming approach said to have led to the decades-old haze problem in the region.

For Malaysia and Singapore, Indonesia’s reluctance to reveal the concession maps remain a major stumbling block to efforts to identify the companies and punish them as one of the deterrent measures to a recurring haze problem that is said to be costing businesses billions of dollars.

Indonesia’s environment minister Balthasar Kambuaya has cited legal issues as its main reason against full disclosure.

“Of course we didn’t get what we want but it is a step forward,” Singapore’s Minister of Environment and Water Resources told reporters after the 15th meeting of the Sub-Regional Ministerial Steering Committee (MSC) on trans-boundary haze pollution.

Malaysia and Singapore say that the proposal, pending its approval by at the ASEAN Leaders Summit this October, is a step forward as Indonesia gave its assurance that it would not have a problem with sharing the concession maps as a part of the group’s plan to adopt a pre-emptive sub-regional Haze Monitoring System (HMS).

Large-scale burning to clear land for palm oil plantations on Indonesia's Sumatra island have been blamed for an annual haze choking neighbouring Singapore and Malaysia. The winds that swept the smoke eastwards last month was belileved to be the worst in more than a decade.

The heavy air pollution over the region has turned off tourists, forced schools to close and caused a rise in respiratory illnesses.

Indonesia is the only member that has still not ratified ASEAN’s Agreement on Transboundary Haze Pollution, brokered in 2002.

The treaty aims to stop cross-border smog from forest fires by requiring parties to prevent burning, monitor prevention efforts, exchange information and provide mutual help.

It also binds signatories to “respond promptly” to requests for information from another country hit by the smoke, and to take steps to implement their obligations under the treaty.

Indonesia, a freewheeling democracy since the fall of strongman Suharto in 1998, has blamed its parliament for the long delay.

Jakarta had sought its lawmakers' approval to ratify the haze agreement but the proposal was rejected in 2008. The pact has been submitted again to the legislature.

The ministers today warned that haze could be expected until the end of the southwest monsoon season in October if there was an increase in hotspots.

Kambuaya said Jakarta was prepared to share concession maps of fire-prone areas with other governments, but they would not be made available to the public as Singapore had asked.

“We are not allowed to publish concession maps with the public,” he said.

The concession maps show who has the right to plant crops or log a particular tract of land, allowing them to be investigated and prosecuted for fires.

Meanwhile, Natural Resources and Environment Minister Datuk Seri G. Palanivel said Malaysia has no problems in sharing the concession maps of its Indonesian-based companies.

"We don't have any problems with that but the Indonesians have certain rules," he told the same press conference.

Palanivel added that today's meeting saw ministers agreeing on the need for better early warning systems as the best way to prevent a recurring haze problem.

"I think we agreed that deterrent is the best way for now," he said.

The minister added that Malaysia and Singapore will also provide logistic aid to help Indonesia fight wildfires in the future.