Vandalism to Metrorail infrastructure in Cape Town has resulted in more than R1-million worth of damage and has shut down the False Bay section of the rail service for a week.

On Sunday, Metrorail's Protection Services prevented the theft of an 11 kV line but, in the process, the suspects threw the cut 11kV line onto live 3kV overhead electric wires, according to Metrorail spokesperson Nana Zenani.

The two wires touched, causing damage to four mast poles in what Zenani described as an "emergency situation" on the southern line in False Bay.

"Metrorail will not be able to run services on the southern line, specifically between Retreat and Fish Hoek. The damage to the mast poles and overhead electrical lines is estimated at approximately R1-million. Metrorail is prioritising the repairs on the line on order to get the service running," Zenani said.

The line closure is expected to last around a week.

"The budget will have to come from money set aside for normal operations," she added.

The southern line was previously largely unaffected by vandalism, but incidents appear to be increasing, according to Zenani.

Last week, vandalism of rail infrastructure caused a telecommunications outage and resulted in delays across several main railway Cape Town corridors.

"If communities and businesses do not assist in stopping the rampant vandalism, the Western Cape will be without a passenger rail service. Rail is the only source of mass movement and without it, commuters will continue to pay higher transportation costs," Zenani said.

"The illicit copper trade … is the source of problem and why criminals are targeting and vandalising our infrastructure.  We need stringent interventions and controls in respect to scrap dealing and the export of copper. The very relaxed regulations around the sale of copper is causing Metrorail serious harm in its ability to deliver on its mandate to operate trains."