The City of Tshwane is on high alert for flash floods after the weather service warned of a 60 percent chance of showers at the weekend.

"As a result of the rain, flash floods may occur, especially in low-lying areas," the city said in a statement.

Areas that have proved vulnerable to flooding include Centurion, Mabopane, informal settlements and low-lying bridges.

Motorists were urged to drive carefully, avoid speeding and be on the lookout for debris on the roads.

"The metro police will monitor roads and will be at intersections should there be a need," the city said.

The Disaster Management Centre would be "fully activated" if needed. - Sapa