A South African union branch leader was shot dead Friday evening in a northwestern town where violent strikes at the Lonmin platinum mine have already left 46 dead, the union said.

"A branch secretary of the union at Western Platinum was shot and killed at his house in Marikana this (Friday) evening," said National Union of Mineworkers spokesman Lesiba Seshoka in a statement.

The death comes a day after police shot dead a mineworker at an Anglo American Platinum mine in neighbouring Rustenburg while trying to disperse a group of strikers.

At least seven people have been killed around Rustenburg in strike-related violence this week.

A NUM branch chairperson was killed last weekend and another escaped while his wife was killed, added Seshoka.

"The union and its members are gradually losing confidence in the ability of the police services to protect innocent civilians," he said.