A satellite observation on Sunday detected more hotspots on Indonesia's Sumatra and Borneo Islands.
On Sunday morning, the satellite detected 151 hot spots across the nation, comprising mostly of islands, significantly rising from 59 hotspots found nine days ago, said Sutopo Purwo Nugroho, spokesman of the national disaster management agency.
Of the total hotspots, 57 of them were discovered in Sumatra, mostly in Riau province, and the 83 others in Borneo, Sutopo told Xinhua news agency.
He said agriculture and forest fires have occurred in both islands since February due to lack of water supply which has hampered firefighters to douse the blaze.
Riau province, home to the world's largest palm oil industry, has frequently endured forest fires as people burned land clearing for new plantation.
Last year, the Indonesian government launched the biggest ever battle against massive forest fires occurring across the country, involving thousands of soldiers and scores of aircraft with assistance from foreign countries.
