Four babies have died over the past nine days after suffering from lung infections in the South Sumatra capital of Palembang, the Kompas daily reported yesterday.
Darent Saputra Tambunan, the latest victim, was just 27 days old when he died on Tuesday.
He was diagnosed earlier with a lung infection - the same diagnosis as for the three other infants - and had breathing difficulties.
More than 136,000 people in Indonesia have reportedly suffered from respiratory illnesses after being exposed to the haze from illegal forest fires in Sumatra and Kalimantan.
There were also unverified reports of other deaths related to the haze, including that of a 15-year-old schoolgirl, since the haze crisis started in August.
The Pollutant Standards Index in Palembang peaked at 530 yesterday - above the hazardous zone of 350 - before going down to 212 at 6pm yesterday.
The dry weather in Indonesia, which has been made worse by an extended El Nino season, has made it harder to put out fires, despite help from a multinational firefighting assistance team now in South Sumatra.