Indonesia's President Joko Widodo will cut short his trip to the United States on Tuesday to help deal with clouds of smoke large areas of his country.

Thousands of fires caused by slash-and-burn agriculture in Indonesia's forests have forced schools and offices to close and airlines to cancel flights.

Indonesia's disaster agency says fires in Kalimantan and Sumatra have left 10 dead, some burned while fighting the blazes and others overcome by pollution.

"President Joko Widodo has decided to hasten his visit in the US to return home," said presidential spokesman Ari Dwipayana.

Widodo is now due to leave Washington late Tuesday, by which time he will have completed planned meetings in the capital, including with President Barack Obama.

But he will not head to America's West Coast as planned to meet with US tech sector executives and will instead dispatch ministers in his stead.

Indonesia has deployed 30 aircraft to fight the fires and for cloud seeding, with 22,000 troops on the ground and a flotilla of warships on their way.

At least half a million people have suffered from respiratory illness since the fires started in July and 43 million people live in the affected area.