A Christchurch family has had their faith in humanity restored after the other party in a car crash bought them a new car.

A Christchurch family has had their faith in humanity restored after their only car was replaced by the driver who collided with it.

Savannah Ward, who is 28 weeks pregnant, was driving her parents' Subaru Impreza on Wainoni Rd last Friday, when she attempted a U-turn in front of a van.

The oncoming driver, Roland Ipenburg, was unable to stop.

KIRK HARGREAVES/ FAIRFAX NZ Savannah Ward, who is pregnant, has been gifted a new car by the man she had a collision with.

Ipenburg, an electrician, said he could tell "things weren't right" when 18-year-old Ward was holding her stomach.

She fainted on top of a stranger, who had arrived to help, and lay unconscious on the roadside.

Soon after, Ward began having premature contractions.

Ipenburg, who was uninjured, said he was "shocked" to see Ward, who was driving by herself on a learner licence, in such distress.

"Any finger-pointing really went out the door," he said.

"Our main concern was her wellbeing, and the baby's wellbeing."

A St John ambulance took Ward to Christchurch Hospital, where she stayed for about four hours.

Ward's mother, Angela van Limburg, arrived on the scene minutes after the crash. The car, which was uninsured, was "an absolute, total write-off", she said.

The family were unsure how they would cope without their shared vehicle, until Ipenburg called them with an incredible offer. He would buy them a new one.

"We thought it was a joke," van Limburg said.

Ipenburg said when he told wife Jan what had happened, she had suggested they replace the family's car.

"[We thought] they'd most probably need a vehicle, especially with young baby coming," he said.

Van Limburg's husband Wilco rung Ipenburg to confirm the request was genuine but the couple still had doubts.

"We were like, 'OK, we'll believe it when we see it'," van Limburg said.

"This just doesn't happen."

On Tuesday, staff from Wheeler Motor Company delivered a 2002 Nissan Pulsar to the van Limburgs' Linwood driveway.

Van Limburg said she wanted to share the family's story because she did not know how else to thank the Ipenburgs.

Ipenburg said he and his wife were happy to help.

"We're not super wealthy but we can sort of afford to do the things we actually want to do," he said.

"I started off with humble beginnings and I know what it is like."