Eyewitness News has learnt that a woman injured in this week's SA Roadlink bus crash near Beaufort West has been left paralysed.

Seven people were killed when a bus careened off the N1 Highway on Tuesday morning and overturned.

More than 30 people were injured ? three of them seriously.

It's also understood the paralysed woman's child was among those killed.

Meanwhile, the Transport and Omnibus Workers Union has joined the chorus of concern over SA Roadlink?s safety record on the country?s roads.

"We've had over the last few months almost on a weekly basis cases at the CCMA where workers have been dismissed because workers were raising their concerns about safety; hours that they were working and so on," says union spokesperson, Gary Wilson.