Commuters cross a bridge as thick haze blankets Pekanbaru in Indonesia on September 16, 2014

Indonesia's parliament on Tuesday voted to ratify a regional agreement on cross-border haze as fires ripped through forests in the west of the country, choking neighbouring Singapore with hazardous smog.

Officials in Singapore and Malaysia have responded furiously to Indonesian forest fires, which have intensified and become more frequent in recent years.

Singapore's rose to unhealthy levels on Monday as Indonesian authorities failed to control fires in Sumatra island's vast tracts of tropical forest.

Parliament's decision has been passed into law.

The agreement obliges Indonesia to strengthen its policies on forest fires and , actively participate in regional decision-making on the issue and dedicate more resources to the problem, regionally and domestically.

Indonesia signed the ASEAN Agreement on Transboundary Haze Pollution 12 years ago and has been under increasing pressure to ratify the document, beginning deliberations in earnest in January.

"Indonesia has already carried out operations for the prevention, mitigation of and haze, and recovery activities, at the national level," parliament said in a statement.

"But, to handle cross-border pollution, Indonesia and other ASEAN nations recognise that prevention and mitigation need to be done together," it said.

While Singapore and Malaysia are smothered in haze from Indonesian forests every year, fires in June last year caused the region's worst pollution crisis in a decade, renewing calls for action in Indonesia.

Commuters travel along a road as thick haze blankets Pekanbaru in Indonesia on September 16, 2014

Authorities have said most of the fires are deliberately lit to clear land for commercial plantations, such as paper and palm oil, and have arrested people caught in the act.

The June 2013 haze crisis sparked a diplomatic row with Indonesia claiming Malaysian and Singaporean companies with plantations on Sumatra and Indonesian Borneo were among those starting the fires.

Singapore last month passed a bill that gives the government powers to fine companies that cause or contribute to haze up to Sg$2 million ($1.6 million), regardless of whether they have an office in Singapore.