Cosatu in the Western Cape called on farmworkers across South Africa on Sunday to join a wide-scale agricultural strike.
Workers were calling for "one day of action across the whole agriculture sector across South Africa" on Tuesday, said Congress of SA Trade Unions (Cosatu) Western Cape secretary Tony Ehrenreich.
He said in a statement that, despite their best efforts, the unions would not be able to avert a renewed strike by farmworkers in the Western Cape on Tuesday.
Two people have been killed and buildings and vineyards have been set alight so far in the protests, which started last month in 16 towns, including De Doorns, Wolseley and Ceres.
Farmworkers suspended the action until Tuesday on condition the employment condition commission relook at the sectoral determination for agriculture.
However, Labour Minister Oliphant said this week that the sectoral determination, which came into effect in March, could by law be reviewed only in 12 months.
"The farmers, who were previously committed to find an agreement through good faith negotiations, changed their attitude to negotiations," said Ehrenreich.
They said they were not prepared to offer workers an increase.
"The right-wing elements in the farmers' group have now taken control and are hiding behind the minister's sectoral determination process."
He said a coalition of farmworkers and unions announced on Thursday that the strike in demand of a wage of R150 a day and better living conditions would resume on Tuesday. Most of them earn between R69 and R75 a day.
Ehrenreich said the farmworkers had been let down by the country.
"In spite of...[workers] bending over backwards to find solutions, no one is prepared to listen or work towards solutions with them."
He said farmers did not deny that they could afford to pay higher wages.
"They are really saying that if they treat the workers humanely in this sector, then workers would be demanding to be treated humanely in all sectors, and they can't have this," he said.
"They would rather spend their money on security guards.... They would rather assemble their private right wing armies on the farms."
He said there were "good" farmers, who did not agree with the "right-wingers" and were talking to unions to find a solution.