Firefighters work at the scene of a deadly blaze in the early hours of the morning, in Johannesburg   / Photo: Reuters

South Africa’s emergency services say at least 73 people have died in a fire that ripped through a multi-story building in Johannesburg in the early hours of Thursday.

Emergency Services spokesman Robert Mulaudzi said another 43 people were injured in the blaze that broke out in the predawn hours. He said the death toll might still increase.

A search and recovery operation was underway and firefighters were moving through the building, Mulaudzi said.

The team had initially pulled 52 bodies out, he said, adding that more people might be trapped inside. At least one child was among the dead, Mulaudzi said.

Women react after a deadly blaze in the early hours of the morning, in Johannesburg. / Photo Reuters

Authorities said the fire had been largely extinguished, but smoke still seeped out of windows of the blackened building downtown. Strings of sheets and other materials also hung out of some of the windows.

It was not clear if people had used those to try and escape the fire or if they were trying to save their possessions.

Mulaudzi said the building was effectively an "informal settlement" where homeless people had moved in looking for accommodation without any formal lease agreements.

He said that made it hard to search the building. There might have been as many as 200 people living in the building, witnesses said.

AP