At least 52 people have reportedly died in a fire in a multi-storey housing complex in South Africa’s biggest city, emergency services say.

Another 43 people were injured in the blaze in Johannesburg, which broke out in the pre-dawn hours of Thursday (local time), Emergency Management Services said.

The death toll has been climbing as the search-and-recovery operation was under way.

Harrowing images show bodies under sheets lying on the sidewalk as emergency workers gathered the victims.

Spokesman Robert Mulaudzi said it was likely there would be more people found dead.

The team had pulled 52 bodies out so far, he said, adding more people might be trapped inside.

At least one child was among the dead, Mr Mulaudzi said.

Authorities said the building was used by homeless people. Photo: Getty

Authorities said the fire had been largely extinguished, but smoke still seeped out of windows of the blackened downtown building.

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.

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Mr 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.