Correctional Services said that “matters are under control” at Johannesburg’s Sun City Prison on Wed.
Thousands of truckers countrywide will go on strike soon.
The strike comes after negotiations with the country's road freight employers collapsed.
"The South Africa Transport Workers Union has issued a notice that the strike can commence any time," said union spokesman Ronnie Mamba.
The nationwide strike means that the delivery of goods, especially food and cash, to retailers and banks will come to a halt.
The industry employs long-distance truck drivers, cash-in-transit workers and general goods truck drivers.
Mamba said workers wanted an 11percent salary increase.
He said employers were offering a 7percent increase.
Mamba said: "We are also negotiating the issue of retrenchments and the issue of allowances, especially for cross- border truckers who work under unsuitable conditions." - With Sapa