Firefighters in Indonesia have been combating wildfires across the country, but the huge scale of the smoke and flames is starting to affect the air of neighbouring countries.

Footage shows crews working to extinguish the flames engulfing palm trees in Pekanbaru on May 20.

Media reported that the thick haze from wildfires in Indonesia is affecting the air quality in neighbouring Singapore and Malaysia where air pollution is rising above the ''healthy'' level.

Wildfires across Sumatra's Riau province are causing air quality to drop at hazardous levels and forcing residents in the capital to stay indoors.