As a car that had just crashed lit up in flames, members of the public rushed to try and break into it in an effort to free those trapped inside.

Kevin Clark was driving on Summit Rd, on Christchurch's Port Hills, when he came across the scene of an accident about 11pm yesterday.

"It was just after the accident [and] there was a group of people looking for a knife so they could help someone trapped in the car.

"I had a craft knife in the back of my car. I quickly grabbed it and handed it over."

Clark said about six to eight cars had already stopped when he arrived.

The scene of a fatal crash at Summit Road in Christchurch late last night. Photo / Kevin Clark

"The car had gone off the road and was on fire," he said.

"People were trying to get the fire out with whatever water they could find."

He could not go down towards the vehicle himself as he was barefoot.

Those who had stopped to help before he arrived told him there were at least three people inside the vehicle and that they were trapped.

Emergency services arrived about five minutes later and vehicles that had been at the top of the hill became blocked in as a result.

Police later confirmed a person had been killed in the late-night crash and that one other person was in hospital in a critical condition.

A person has been killed in a crash in Christchurch overnight. Image / Google

Five fire crews were sent to the scene just before 11pm, a southern fire communications spokesman told the Herald.

Fire investigators were also sent out to the site and were due back there today, he said.

The immediate surrounding area between Bridle Path and Dyers Pass Rd was closed for some time as authorities worked to retrieve the car involved.

Walking tracks in the vicinity are also closed today.

The fatal crash followed a number of other serious car crashes around the country last night.

One person was taken to Waikato Hospital in a serious condition after falling from a moving vehicle in Te Kōwhai - a small rural town about 15km north-west of Hamilton.

St John said an ambulance attended the scene shortly after 6.30pm.

About 9.20pm, emergency crews were called to a crash on State Highway 67 in Granity on the West Coast.

One person was taken to Westport Hospital in a serious condition.

Just before 1.30am today, authorities received reports of a crash on Cust Rd in Cust, North Canterbury.

St John staff and a helicopter were dispatched to the site, where a person had suffered serious injuries.