At least 75 people were injured on Thursday when an SA Roadlink bus crashed on the N3 freeway in the KwaZulu-Natal midlands, paramedics said.

Netcare 911 spokesperson Chris Botha said paramedics treated 75 patients. One was critically injured, 14 were seriously injured and 60 had minor injuries.

He said the seriously injured were taken to a Pietermaritzburg hospital.

Inspector Joey Jeevan said the SA Roadlink bus collided with another bus and five other vehicles in Lions River in the midlands.

ER24 spokesperson Derrick Banks said both buses were fully laden and that the Roadlink bus was a double-decker.

"Over 40 people have been injured. The driver of the SA Roadlink bus has been being extricated and is in a critical condition."

Witnesses on the scene told Sapa that the SA Roadlink bus had hit into the back of another bus which was signed 'Ebhodwe Transport'.