JOHANNESBURG (Reuters) - Labour unrest sweeping across South Africa's platinum sector hit Anglo American Platinum on Wednesday, with striking miners blockading roads leading to shafts belonging to the world number one producer, police said.

"Around 1,000 mineworkers had a confrontation with mine security last night at the Siphumelele shaft and the situation has spread to other mine shafts this morning," regional police spokesman Thulani Ngubane said.

Siphumelele is one of four mines near Rustenburg, 100 km (60 miles) northwest of Johannesburg, that have been targeted as "restructuring candidates" by Amplats parent company Anglo American.

Shares in Amplats, which has largely avoided the unrest this year that has hit rivals Impala Platinum and Lonmin, fell 3.6 percent. Anglo American, which owns roughly 80 percent of Amplats, shed 3 percent.

Amplats said miners at its Rustenburg operations were "not on strike", but said it was "aware of widespread cases of intimidation".

"We confirm that yesterday, some of our employees were unable to clock in for night shift due to fear of intimidation and threats by unidentified individuals in and around our Rustenburg operations," it said in a statement.

The price of platinum spiked 1.5 percent higher amid fears of further disruption to supplies of the precious metal, which is used in jewellery and vehicle catalytic converters.

Platinum has now gained more than 17 percent since South African police shot dead 34 striking miners at Lonmin's Marikana mine, also near Rustenburg.

(Reporting by Ed Cropley; Editing by Ed Stoddard)

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