Indonesia has sent nearly 21,000 personnel to fight fires on its northern islands that have spread haze to neighbouring Singapore and Malaysia, the country's disaster management agency says.
Heavy smoke from "slash-and-burn" clearances often comes from the Indonesian islands of Sumatra and Kalimantan, where palm oil companies have large forest concessions.
Indonesian efforts to halt the seasonal clearances have failed.
This season's haze has blanketed the region in a choking haze for weeks, pushing up pollution levels and disrupting flights, as it does every year.
More than 135,000 Indonesians were reported to be suffering from respiratory diseases, Indonesia's National Disaster Mitigation Agency (BNPB) said.
The acting governor of Riau province on Sumatra Island, Arsyadjuliandi Rachman, said a state of emergency would be extended for two weeks due to the smog.
"Our focus will remain on monitoring the health of our people," he said.
Schools in parts of Malaysia were ordered closed for a second day on Tuesday and Singaporean commuters were wearing masks as they have for much of the last two weeks.
Earlier this month, Indonesian authorities deployed 1,000 soldiers to put out the fires in south Sumatra province, one of the main hotspots.
The BNPB said, if necessary, the agency would also send in additional helicopters to help water-bomb the fires.
Indonesia defends handling of haze crisis
Indonesia has faced criticism for turning down offers of help from Singapore, even as it struggles to contain fires that have been exacerbated by a prolonged dry season.
Indonesian officials have repeatedly said they have enough resources to handle the crisis.
Vice president Jusuf Kalla said neighbouring countries should be grateful for clean air provided by Indonesia's rainforests outside the haze season.
Mr Kalla this week toned down his earlier comments and said Indonesia was open to foreign assistance, according to media.
President Joko Widodo last week reportedly visited Central Kalimantan and called for urgent action including building canals to irrigate parched peatlands where fires can be harder to put out.
The Indonesian government has launched investigations of more than 200 companies and taken legal action against just four.