Several roads in and around Johannesburg have been blocked off due to a cycle race.

Thousands of cyclists are taking part in the annual event that started on Sunday morning.

The Cycle challenge started and will finish at Riversands Commercial Park in Fourways north of Johannesburg.

The M1 south will be blocked off from Buccleuch interchange up until Carr street in Newtown, Jan Smuts Avenue, Witkoppen road and parts and Malibongwe avenue and Riversands boulevard will be blocked off.

Motorists can use the N1, William Nicol, Rivonia road and Oxford road to access Sandton or Rosebank.

Officers will be on duty to divert traffic along the route.