Hazy conditions on Tuesday evening were due to hot spots in southern Johor, and PSI and fine particle readings are expected to be moderate for the next 24 hours, the National Environment Agency said in an advisory.
At 9pm, the three-hour PSI was at 76. The 24-hour PSI readings for different parts of the island ranged from 31 to 57 while the 24-hour PM2.5 reading of fine particulate matter ranged from 17 to 43 micrograms per cubic meter.
The number of hotspots detected in Peninsular Malaysia rose to 149 on Tuesday from 86 on Monday, while those in Sumatra numbered 259, up from 228, the agency said.
In a Facebook post on Tuesday night, Environment and Water Resources Minister Vivian Balakrishnan said: "We will try to contact the Malaysian authorities, and offer assistance if needed."
For the next 24 hours, the 24-hour PSI and PM2.5 are expected to be in "the higher end of the Moderate band", said NEA. "However, we expect the haziness to improve over tomorrow night."
The weather is expected to be dry and warm for the next few days and hazy conditions can be expected if hotspots in Johore persist.
While healthy people can continue with normal activities, those who have chronic heart or lung conditions, elderly people, pregnant women or young children, should seek medical attention if they do not feel well.