Strikers were turning away trucks and buses in the Wolesley area to stop non-striking farm workers to go to work on Wednesday, SABC radio news reports.
They had also closed a road into a nearby township.
It was also reported that farmers in the Hex River Valley had employed private security personnel to protect their property against strikers.
Western Cape farmworkers went on strike last year, demanding that their daily wages be increased from R69 to R150. They also wanted a coherent land reform programme.
Two people were killed and property worth millions was destroyed between August 27 and December 4. The strike was then suspended.
Last week the Congress of SA Trade Unions (Cosatu) announced that the strike would resume on Wednesday following failed pay negotiations with Agri-SA and government.