KOSAMBI (Java) • The owner of a fireworks factory in Java, Indonesia, where 47 workers died after a blaze tore through the building is being questioned, police said yesterday, as labour organisations pointed out that the incident has exposed inadequate workplace safety standards.

The ferocious fire on Thursday at the factory in Tangerang, near Jakarta, was one of Indonesia's worst industrial accidents in recent years.

Jakarta police spokesman Argo Yuwono said investigators were still scouring the burnt-out scene and had begun interviewing witnesses, including three staff members and the factory owner.

"When the incident happened the owner was in Malaysia, but he immediately returned upon hearing (about it) and he has been questioned," Mr Yuwono said.

Tangerang police chief Harry Kurniawan said the authorities were still investigating the cause of the fire and denied reports that the gates at the factory had been locked.

"According to eyewitnesses who were injured and are now at the hospital, some of the victims escaped or were rescued through the main gate, so the gate was open," Mr Kurniawan said.

Officials have warned that the death toll could rise.

Police said there were 103 workers employed at the factory at the time of the disaster and confirmed that 47 people died, while 46 people are being treated in hospital.

Three people did not attend work on Thursday and seven are still unaccounted for.

Tangerang General Hospital spokesman Yudi Firmansyah said the hospital was treating 12 patients, some of whom had burns to up to 80 per cent of their bodies.

"We're an emergency unit so we've seen these things before. But this is a special case because it was a mass event," he said.

"We are expecting treatment to take a long time. First there's the life-saving stage, then further treatment to prevent infections, and then cosmetic procedures," added Mr Firmansyah.

AGENCE FRANCE-PRESSE, REUTERS