Indonesian police have arrested 72 people suspected of deliberately starting forest and peatland fires that have produced dangerous haze across parts of the country.

The suspects are being investigated in connection with 89 fires across several provinces on the islands of Borneo and Sumatra, with many accused of burning land to clear areas for plantations.

Authorities are also investigating whether companies financed or ordered the fires, and suspects could face large fines or up to 15 years in prison.

President Prabowo Subianto visited Central Kalimantan, where more than 7,600 hectares have burned, and promised government resources to help contain the fires, the AP has reported.

The smoke has spread across Borneo and into neighboring Malaysia, while Indonesia reported more than 3,700 fire hot spots as officials work to control the worsening haze.