An Indonesian city with a population of hundreds of thousands has shut schools for three days because of haze caused by large peatland fires, its mayor said Tuesday.

A prolonged dry season has caused higher risks of wildfires on the archipelago nation's major islands, stoking fears of repeat haze-belching forest fires that have also affected neighbouring Malaysia and Singapore in recent years.

The city of Jambi on the western island of Sumatra, which has a population of around 600,000, has forced students to online learning from home over the toxic smog.

"The thick smog made us lay off students from preschool to junior high school," the city's mayor Syarif Fasha told reporters at Jambi city hall.

The school ban was from Monday to Wednesday, but would be extended if the haze continued, he said.

Authorities said the haze was caused by fires elsewhere, without specifying. Peatland fires have been raging in neighbouring Palembang province for more than a month.

On Monday, air quality levels in Jambi reached 154 PM2.5 -- fine particles that can penetrate deep into the lungs -- at "unhealthy" levels 11.4 times the annual air quality value set by the World Health Organization (WHO).

The local government has also asked residents to wear masks and reduce outdoor activity as the air quality deteriorates.

It has been distributing masks on the street and at markets, according to an AFP journalist.

Schools in Palembang in South Sumatra and Banjarmasin in South Kalimantan -- all affected by haze -- have also shifted to online classes, according to local media reports.

Parents in Jambi said they agreed with the decision.

"The haze is dangerous for health," said 35-year-old office worker Kusnadi Putera.

"There are additional costs (of children at home), but we have got used to it since the pandemic."

Siti Jamilah, a 55-year-old housewife in Jambi, said she was avoiding leaving the house apart from trips to the market for food.

"The eyes feel sore, and the air smells like something is burning," she said.