Heavy rains have killed 16 people in South Africa's largest city Johannesburg in the last two weeks, an official said on Saturday.

"Thus far, 23 people have been rescued by Joburg Emergency Medical Services and 148 people have been rescued by the police search and rescue," Executive Mayor of Johannesburg Mpho Phalatse said at a media briefing.

The torrential rains have damaged property, fauna and flora, and essential infrastructure, particularly roads, traffic lights, buildings, substations, power stations and pipelines, she said.