Global miner Anglo American announced Wednesday that it has suspended platinum operations in Rustenburg, South Africa, in order to protect its employees amid ongoing labour unrest.

"Anglo American Platinum announces the suspension of its Rustenburg platinum operations in order to protect the safety and security of its employees from outside intimidation," the world's top platinum producer said in a statement.

Hundreds of people barricaded roads leading to the mine as labour unrest spread in South Africa's key industry, police said.

"Our employees are not on strike," added Anglo American Platinum chief executive officer Chris Griffith in Wednesday's statement.

"However, in light of the current volatile situation in the Rustenburg area, where our employees, who want to go to work, are being prevented from doing so and are being intimidated by the threat of violence, Anglo American Platinum has decided to suspend its operations in the Rustenburg area with immediate effect.

"The suspension will continue until such time as operations can be safely resumed," added Griffith.

Cynthia Carroll, chairman of Anglo American Platinum and chief executive of parent group Anglo American, stressed on Wednesday that the safety of employees was the group's "absolute priority".

South Africa's mines have in recent weeks been hit by unrest following a wildcat strike at Lonmin's Marikana platinum mine that has so far claimed 45 lives.

On Tuesday, maverick politician Julius Malema called for national strikes across all South African mines for five days each month, to fight for a basic salary of 12,500 rands (around $1,500) -- around three times the current average.