JAKARTA (Bloomberg) - Indonesia's President Joko Widodo is heading to Borneo and Sumatra islands to check on efforts to stop forest blazes that are causing pollution across the region.

Mr Joko, who has set a deadline of two weeks to a month to stop the burning, will speak to fire fighters in southern Kalimantan on Borneo on Wednesday and then head to Sumatra for two days, his office said in a statement.

A pollution gauge in Pontianak in Kalimantan worsened to 779.4 on Wednesday, double the level considered hazardous, while in Singapore a three-hour index was up to an unhealthy level of 116 as of 11 a.m.

Mr Joko, known as Jokowi, is facing regional pressure to step up efforts to combat perennial forest burning by cracking down on companies with fires on their concessions. The government on Tuesday said it suspended the permits for three Indonesian palm oil planters and revoked the permit for a forestry company.

"There are 14 companies that are being investigated by police," said Mr Fadrizal Labay, the head of forestry and plantations for Sumatra's Riau islands, near Singapore. "There will be a possibility of criminal and administrative action."

PT Langgam Inti Hibrindo, one of the palm companies named by the government and majority-owned by PT Provident Agro, said on Tuesday it was not responsible for causing any fires and will cooperate with the authorities.

Responsibility for the blazes, which also emit greenhouse gases from burning peatlands, is complicated by uncertainty over land rights and overlapping permits in a country with widespread official corruption.