Muhammad Khaeron of the meteorology office in Pontianak said low visibility from the haze had delayed the landing of one commercial flight from Jakarta by about 45 minutes on Monday.
Smoke haze is beginning to cover western Borneo and the Indonesian island of Sumatra, as well as parts of southern Thailand.
In 1997, vast fires left a cloud of thick smog across large areas of south-east Asia, causing environmental damage and an estimated $9.3bn in economic losses.
The smog, which is highly toxic, is thought to have been caused by farmers using fires to clear their land.
Flight delay
"Dense smoke haze has returned over Pontianak but only during the nights, while during daytime, visibility returns to normal," said Idrin, the head of West Kalimantan's environmental office.
Muhammad Khaeron of the meteorology office in Pontianak said low visibility from the haze had delayed the landing of one commercial flight from Jakarta by about 45 minutes on Monday.
He said the haze in Pontianak, which had thickened in the past 10 days, was worse at night because of the presence of mist.
Haze has also returned to the Indonesian provinces of Riau, on Sumatra island - the area worst hit by forest and ground fires in 1997-98.
"It is definitely back," said Sarman, of the meteorology office in the Riau provincial capital Pekanbaru. "We have been seeing the haze here again, especially in the early morning, for the past four days."
He said the haze had so far not affected flights, although early in the morning visibility was less than 500m.
Fire season
The environmental official in Pontianak said preliminary investigations showed the haze on Borneo had resulted from farmers lighting fires in the late afternoons.
"This is almost planting season again, and the farmers are cleaning their land for the new crop," said environment official Idrin.
"What the governor and his underlings have been actively doing in the past days is to tell the farmers that if they want to use fire to clear their land, they should at least wait until the grass is really dry before they burn it, so that there is less smoke."
The government has banned plantations and large companies from using fire to clear their land, but it has been unable to enforce the ban on small farmers.
Officials in Thailand said smog from forest fires on Sumatra had floated across several southern Thai provinces over the weekend.
In some areas, visibility was down to less than 100m on land, and coastal radio said visibility at sea was less than one kilometre (half a mile), the Bangkok Post reported.