South African police on Wednesday fired rubber bullets to disperse a crowd gathered near a mine owned by the world's number one platinum producer Anglo American Platinum, a spokesman said.

"They refused to disperse. Police had to revert to tear gas and stun grenades and there was also rubber bullets fired," police spokesman Dennis Adriao told AFP, saying the people had gathered illegally in an informal settlement.

Anglo Platinum spokeswoman Mpumi Sithole confirmed to AFP that tear gas was fired "at Sondela informal settlement."

The company said on Tuesday that operations returned to normal levels after it reopened five of its South African mines in the Rustenburg platinum belt northwest of Johannesburg, though "many" workers still had not returned to work.

Attendance figures for Wednesday were not immediately available.

Amplats workers committee representative Gaddhafi Mdoda said he had visited four shafts on Wednesday and that "there is a lot of unrest". Workers had only returned to one shaft and the strike had not ended, he said.

"That's the only one. Otherwise all the shafts are closed, no-one has gone back to work," he said.

The police have acted swiftly to stamp out illegal gatherings, carrying of weapons and threats of violence that have marked weeks of unrest on mines since the government announced a major security clampdown on Friday.

"The cops are shooting people even... driving the hippo (armoured vehicle) over the worker who was lying down because they shot him with the rubber bullets," Mdoda said. Police could not confirm any injuries.

Amplats had closed down its five mines last Wednesday over safety fears after intimidation threats on miners going to work.

It became the second mining giant to be hit by strikes in the Rustenburg platinum belt where it employs 24,000 people, after a wildcat strike which started at the neighbouring Lonmin mine on August 10 left 45 people dead.

Thirty-four were shot dead by police on August 16 in bloodshed that shocked the world with its echoes of police brutality under the white apartheid regime.

Lonmin workers on Tuesday agreed to return to work after the company agreed to a 22-percent salary increase.