A fresh round of labor unrest hit the strike-stricken Lonmin Platinum Mine in Marikana, the North West Province on Tuesday, authorities confirmed.

The labor action involved about 6,000 workers who demanded that offices of the National Union of Mineworker be closed down because the union, whose influence was shrinking, no longer represented the workers.

"Employees at four of our shafts did not show up for work this morning," Lonmin spokesperson Bernard Mokoena said, adding "we had several meetings with them and their concerns were that they would like the NUM offices to be closed."

NUM has been fighting with the Association of Mineworkers and Construction Union (AMCU) for dominance among the workers. Their rivalry has often led to violent clashes.

The Lonmin Mine, the world's third largest platinum producer, was the centerpiece of widespread labor unrest in the mining sector last year.

In clashes with police in August, at least 34 Lonmin striking workers were killed in what was believed the worst labor unrest in the post-apartheid era.

Num Secretary General Frans Baleni blamed AMCU for the latest strike.

"It is not tension between NUM and AMCU. The tension is from one side and they chose to demand from management to close down NUM," said Frans Baleni.

Amcu's demand to close NUM's office has been rejected by the Lonmin management. "Our position as management, according to the peace accord, is we would like to see the unions co-exist," Mokoena said.

He said the management has launched talks with the two unions to seek a peaceful solution.

Last month, the Ministry of Mineral Resources, unions and the Chamber of Mines signed a peace accord to restore stability in the troubled mining sector.