Energy Minister Dipuo Peters wants copper theft to be classified as economic sabotage.

Peters told media at the government's Infrastructure Development Cluster briefing on Thursday that her department had written to the Justice Minister Jeff Radebe to suggest that legislation be changed so that cable theft can be classified as a serious offence.

"At the moment cable theft is treated as petty theft," she said.

"A person who steals the copper is a murderer, a thief and a saboteur." The crime, she said, was economic sabotage which disrupted energy, transport and telecommunications service delivery.

Her comments come after stolen cables disrupted the Gautrain for the second time in two weeks on Tuesday between the Hatfield, Pretoria and Centurion stations.

Energy department deputy director-general Ompi Aphane said cable theft had cost the country around R100 million last year, but that the indirect costs to the economy were far higher.

In a statement the cluster said eight people were arrested for stealing copper cable from the ERPM mine in Boksburg in Wednesday.

The Gautrain's operator Bombela Concession Company (BCC) has asked the government to help it fight copper theft and to implement harsher penalties for thieves.