As violent protests broke out in the Western Cape grape valley
"Her deafening silence in the face of this crisis must be challenged," Western Cape Premier Helen Zille and provincial agriculture MEC Gerrit van Rensburg said in a joint statement on Friday.
Oliphant should not hide behind calls to follow official processes, they said.
"It is incumbent on the labour minister to make the first move in defusing the situation, through visible and proactive engagement."
The strike by seasonal farmworkers to have their minimum R69 daily wage increased to R150 – which began late August last year, and was called off at the beginning of December – resumed on Wednesday in De Doorns.
The police used a water cannon, rubber bullets and stun grenades to try and disperse thousands of strikers. The N1 had also been closed at De Doorns.
Zille and van Rensburg said Oliphant needed to get all the parties involved in discussions so the harvest season was not affected.
"Failure to do so will see very severe consequences, not only for the Western Cape but for South Africa as a whole."
Farmers should negotiate
On Friday Oliphant suggested it was farmers who needed to come to the negotiating table.
"I am not convinced that there is a serious attempt by farmers to negotiate," said Oliphant in a statement.
She said farm owners were instead insisting on a sectoral determination process which would hold hearings from next week to relook at the R69 a day minimum wage.
On Thursday, the Cape Orchards Company, representing 12 farms in De Doorns, agreed to talk with various unions.
Meanwhile, the National Employers' Association of South Africa warned strike action would not lead to long-lasting changes.
"Industrial action may force employers to make immediate concessions, but it cannot secure long term employment," the association's CEO Gerhard Papenfus said in a statement.
He added that wage increases had to take "economic realities" into account.
"Any increases which do not fit into a sustainable business model will lead to all kinds of undesired consequences, which in turn will result in unemployment."
Papenfus gave the example of the wage negotiations that took place in the mining sector following wildcat strikes.
Higher wages and retrenchment
He warned that higher wages could also lead to retrenchments.
"One can also not ignore the fact that low earners are finding it extremely difficult to make ends meet. However, it's also true that the millions of unemployed South Africans pose an even bigger threat in the medium to long term," he said.
Also on Friday, the South African Table Grape Industry spokesperson Johan van Niekerk called for urgent intervention to end the strike, and a plan to address socioeconomic problems in the province.
If the strike was not resolved soon, the harvest could be compromised. Farmers could suffer severe losses, which could lead to workers being retrenched. Established export markets could also be lost.
"This will ultimately and irreparably damage the sustainability of the industry in South Africa.
"Finally, and more importantly, farmworkers' lives are being threatened by criminals and the level of lawlessness is causing irreparable damage to brand South Africa," he said. – Sapa