Defence Minister Nosiviwe Mapisa-Nqakula must send army troops to Western Cape rural areas to prevent farmworker violence, says Helen Zille.
She said the army was needed to keep the peace and to prevent workers from violence and arson.
Her request followed Labour Minister Mildred Oliphant's announcement on Tuesday that the December 4 deadline to review the agricultural sectoral determination would not be met.
Oliphant said the Basic Conditions of Employment Act allowed a review of the determination only 12 months after promulgation.
The latest sectoral determination was put in place in March.
Sixteen Western Cape towns were hit by violent protests this month over farming wages and working conditions. Two people died and there was extensive damage to property.
The protests started with table grape harvesters in De Doorns, who were calling for wages of R150 a day. Most earn between R69 and R75 a day.
Workers agreed to suspend their strike until December 4 on condition that the employment condition commission (ECC) look at the sectoral determination for agriculture.
Representatives of both sides have been in negotiations since the strike was suspended.
The Congress of South African Trade Unions (Cosatu) in the Western Cape accused Oliphant of undermining these negotiations with her announcement and said the news could renew strikes.
Cosatu's provincial secretary Tony Ehrenreich said that should a strike go ahead, it would most likely lead to violence and death.
"This strike ... can set back labour relations on farms by decades and could see a reversal to the low-level civil war we all witnessed on farms a few weeks ago," he said.
Zille said Ehrenreich's statement corroborated evidence that some organisations were distributing pamphlets calling for a "day of action and mobilisation" on December 4.
"It is essential that the South African National Defence Force (SANDF) be brought in to hotspot areas so that they can play a peacekeeping role in order to support the South African Police Service (SAPS) to maintain law and order," she said.
"We must do everything we can to prevent the further outbreak of violence on farms in the province."
According to Zille, President Jacob Zuma's spokesman Mac Maharaj had said she was entitled to approach the defence minister to call for such assistance.
"Maharaj responded that there was no need for me to approach the president as he had already authorised the SANDF to support the SAPS in areas around the country." – Sapa