JOHANNESBURG - Strong wind blew off a temporary advertisement structure in western South Africa on Wednesday evening, leaving 20 people injured.

The accident occurred just before 19:00 local time outside the Cape Town Stadium in the western city of Cape Town prior to a concert being held there, the South African Press Association quoted the city's disaster management as saying.

A witness said the advertising structure like a branding tower outside the stadium collapsed suddenly and fell on people below as a strong gust of wind struck it.

The injured had been sent to a hospital nearby for treatment after the emergency personnel rushed to the scene.

The majority of the injured were reportedly women doing promotional work, and the local official said the collapsed structure had been pre-approved and certified safe by engineers prior to the event.

The concert was underway as scheduled despite the incident nearby, according to the report.

It was the latest accident caused by the construction collapse. On Jan 27, a building under construction in Johannesburg collapsed, injuring three people.