The death toll from an explosive fire at a Bangkok live music pub has risen to 32 after two people died from their injuries, the Police Hospital said on Wednesday, as police investigate the possibility of negligence as a factor in the blaze.

The fire, one of the deadliest in recent years in Thailand, tore through the Rong Beer Na Lat Phrao pub in the city's northern Chatuchak area close to midnight on Sunday, with witnesses describing an explosion, a horizontal ⁠burst of fire and smoke engulfing the single-storey venue.

The Erawan Emergency Medical Centre said 30 people were still being treated in hospitals in the city, with 15 of those in intensive care units. A total of 44 people have been discharged.

Authorities believe the fire was probably sparked by an electrical short circuit in a ceiling air conditioner.

Police are investigating the possibility of negligence and if emergency exits were obstructed, as the government vows to tighten regulations over ⁠entertainment venues, including random inspections to ensure fire exits are unobstructed and that venues are safe. The pub had undergone an inspection in April.

The pub, located at a busy intersection next to train stations and two shopping malls, is one of ⁠a cluster of similar bars often crowded on weekend nights, serving food, drinks as well as offering live music and televised sports.

Experts say they think combustible material that decorated ⁠the stage to improve acoustics instantly ignited to produce extreme heat, smoke and toxins, choking the trapped patrons.

The use of flammable materials and decorative items, ⁠crowded conditions and unusable emergency exits in Thai establishments have been previously flagged, including after a fire at another Bangkok nightclub in 2009 that killed at least 65.