The South African Passengers' Organisation (Sapo) has accused Buscor, a Mpumalanga bus company, of failing to heed passengers' warnings about looming accidents.
This follows an accident of one of the company's busses that left 13 people dead and more than 80 hospitalised after it overturned on the R40 road between White River and Nelspruit on Wednesday morning.
Sapo chairman Veli Mathe said the bus company had refused to meet the organisation to discuss, among other things, safety measures and insurance cover for passengers.
"It's high time the company met our demands and told us what we should do to be insured," said Mathe yesterday.
"We also have suggestions about how to prevent these costly accidents, but the company is not ready to meet us."
Buscor spokesman John Ngobe dismissed Mathe's allegations and accused him of being "mentally disorganised".
"We had a meeting with the organisation last month and I don't know what this man is talking about," Ngobe said.
"Maybe he should be booked into a mental institution."
The company was still trying to discover how best to assist families whose relatives either died in the accident or were injured.
Cosatu in Mpumalanga has called for a high-level investigation into the accident, saying many workers had lost their lives and some might not be able to work again.
"Once again, workers have lost their lives while on their way to work," said Cosatu provincial secretary Norman Mokoena yesterday.
"Cosatu wants a full inquiry into the cause of the accident, and appeals to all drivers to exercise restraint on our roads, where far too many lives are being lost."
Meanwhile, a visibly shaken Mpumalanga department of roads and transport MEC, David Mabuza, has dispatched officials from the department to families of victims, to ascertain the kind of assistance they need.
"We want to ascertain if the families can carry the costs of the burials or need help," Mabuza said.
"In cases of need we will assist wherever we can."
The names of those who died in the accident had still not been released yesterday afternoon.
Relatives spent the night at Rob Ferreira Hospital trying to establish whether relatives who had been on the bus when it crashed were still alive.
The double-coach bus was transporting about 100 passengers when it hit a pavement and overturned at about 6.40am.