A body was found in central Johannesburg early Thursday after a blast ripped through a main road at rush hour the previous evening, the emergency services said.

"(In the) early hours of this morning, we managed to recover a body of a male person on site where the explosion occurred," Emergency Management Services spokesman Robert Mulaudzi said.

Mulaudzi added that Forty-one people were injured.

Witnesses reported chemical odours and escaping vapours after the blast, which damaged the road surface and overturned vehicles, including minibus taxis. The road was closed as investigators went through the area.

Panyaza Lesufi, the premier of Gauteng province, which includes Johannesburg and Pretoria, said a preliminary inspection did not reveal the cause of the explosion.

Experts will "get the full view and advise us," Lesufi said.

Emergency services initially blamed underground gas pipes but the city's privatised gas company, Egoli Gas, said it was "unlikely" this was the case as customers were still receiving their supplies uninterrupted.

It issued a statement after an initial inspection, saying a "small leak" had been detected on a supply pipeline, and this was suspected to have been caused "by the collapse of the road."