Following Thursday's violent picket by employees at the Midrand 10111 call centre, the South African Police Service (SAPS) will on Friday bring an urgent application in the Labour Court "to prevent unlawful conduct" by the picketing workers.

Police spokesperson Major General Sally de Beer said, since Friday last week, the South African Policing Union-affiliated 10111 employees on strike at the call centre "have been sporadically intimidating and threatening non-striking employees".

"Yesterday [Thursday] these unlawful acts escalated into them hurling objects at, and damaging, state vehicles," De Beer said.

Acting national police commissioner Lieutenant-General Lesetja Mothiba sanctioned an urgent interdict to be brought on Friday morning, De Beer said.

She said, in the meantime, Mothiba had invited both SAPU and Police and Prisons Civil Rights Union (Popcru) to a meeting on Friday morning, in an attempt to find a way to resolve the strike.

"Contingency plans are still in place at all 10111 call centres, which continue to run efficiently, with the strike having a minimal effect on service delivery," said De Beer.

Problems had only been experienced at the Midrand call centre, she said.

"We call upon SAPU affiliated employees to stop unlawful acts aimed at forcing others to join the strike," she said.

SAPU wants the SAPS to increase their salary level by two notches, an estimated increase of R50 000 per annum.

The call centre employees are employed under the Public Service Act and are thus not considered an essential service.