Two more trucks have been attacked and torched in Cape Town.
One vehicle was attacked on Lansdowne in Nyanga and the other was set alight near the R300 turn-off onto Stock Road.
At least 11 trucks have been targetted across the Western Cape this week, while around 14 have been damaged or set alight in Gauteng since the start of the strike.
The violence is thought to be linked to the ongoing truck driver strike.
Cape Town Traffic Services's Merle Lourens said: "On Stock Road at the R300 we have metro police on the scene, a break-down truck and the fire department is there. We'll be removing that vehicle soon."
Striking truck drivers in Cape Town on Thursday said they blame the attacks on the heavy duty vehicles this week on criminals.
On Thursday, strikers marched to the Road Freight and Logistics Bargaining Council's offices in Parow and handed over their memorandum to officials.
South African Transport and Allied Workers' Union (Satawu) has insisted that its members continue to exercise discipline in their fight for better pay.
Satawu's Cyril Mfukozi said: "We distance ourselves [from the violence]; our members are not hooligans."
Meanwhile, The Cape Chamber of Commerce said there is no immediate solution to the wildcat strikes sweeping the country.
The Chamber's Michael Bagraim said the Labour Relations Act is being undermined and government needs to recognise that it is a disaster.
"We're in the middle of this; we're right in the middle of a disastrous situation and the sooner we realise and recognise it the better. We've got to start talking to each other immediately, both management and staff need to put their difference aside and sit around the table.
"You can't negotiate with someone who is holding you to ransom. So, what we're really asking for is to get back to the very spirit we had in the early days – in the 90s – where people were looking at each other as individuals and as partners in an exercise."
He said the strikes are costing the country millions of rands in lost revenue.