Members of the National Union of Metal Workers of South Africa (Numsa) File photo: Rogan Ward

Rustenburg - Thirteen striking workers have been arrested for allegedly vandalising a building in Rustenburg, North West police said on Wednesday.

On Tuesday at Rustenburg Engineering Centre people who were picketing suddenly started throwing stones at the building, Colonel Sabata Mokgwabone alleged.

Several windowpanes were shattered.

Thirteen people were arrested and would appear in the Rustenburg Magistrate's Court soon to face charges of malicious damage to property and public violence.

By early afternoon on Wednesday no further cases of strike-related violence were reported, Mokgwabone said.

Several unions, including majority union in the sector, the National Union of Metalworkers of SA (Numsa), have been on strike in the metals and engineering sector since the beginning of the month.

Employers' organisations, the Steel and Engineering Industries Federation of SA and the National Employers Association of SA, have complained that the strike had been marked by violence and intimidation.

On Tuesday, national police commissioner Riah Phiyega's office said that in Gauteng alone 53 people were arrested on a single day for strike-related offences.

“The national commissioner does not object to anyone exercising their right to protest, but the law clearly states that this must be done procedurally, unarmed and in a peaceful manner,” Lt-Col Solomon Makgale said.

Phiyega had requested a meeting with Numsa leaders to discuss her concerns about violence accompanying the strike.

Also on Tuesday, Numsa spokesman Castro Ngobese urged union members to be disciplined while on strike.

“As we are engaged in an indefinite national strike, we call on Numsa members participating in the national strike to exercise maximum discipline and not to involve themselves in violent acts of any kind,” he said in a statement.