At least five people died in two separate crashes in KwaZulu-Natal, police and paramedics said.

Four people, including a five-month-old baby, died on Saturday night when the bakkie they were travelling in ploughed through the Umzumbe River bridge.

Captain Vincent Pandarum said a woman, her baby and three other occupants were returning from a party in Umtwalume when the incident took place at 6.30pm.

"The bakkie veered across the right lane and crashed through the metal railings and ended up submerged in the river. Mandla Buthelezi was the only survivor," he said.

Buthelezi managed to swim ashore and was later treated at Port Shepstone hospital.

On Sunday, meanwhile, a tow-truck driver died in an accident on the N2 freeway near Nandi Drive.

Netcare 911 spokesperson Chris Botha said paramedics tried to resuscitate the man but it was too late.

He died at the scene.

The cause of the accident was not known.

Sapa