By Wendell Roelf

CAPE TOWN | Thu Jan 10, 2013 8:56am EST

(Reuters) – South African police fired rubber bullets at rock-throwing farm laborers in the western grape-growing region on Thursday, marking the second straight day of clashes in a country braced for spreading labor unrest.

Hundreds of striking workers seeking higher wages and better working conditions again blocked a major highway running through the town of De Doorns, about 100 kms (60 miles) east of Cape Town, hurling stones at motorists.

The clashes were less violent than on Wednesday, when police arrested more than 40 in areas near De Doorns, one of the biggest vineyard areas for the country’s grape export industry.

This week’s violence points to little let-up in a wave of labor unrest that began six months ago in the country’s platinum mines and then swept through the trucking and agriculture sectors in Africa’s biggest economy.

“All the towns are quiet except for De Doorns, which is a headache,” said police spokesman, Mzikayisi Moloi. No injuries or arrests had been reported on Thursday, he said.

Laborers in South Africa are mostly poor blacks who have seen scant improvement in their financial situation since the end of white-minority apartheid rule in 1994.

The farm workers want to double their salary to 150 rand ($17.45) a day from the 69 rand minimum wage.

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