A doctor on his way to work had a gun pressed into his side in a brazen daylight attack that ended with the man's car being stolen in one of Auckland's wealthiest suburbs.

The man wasn't hurt but another motorist received moderate injuries in a crash soon after that police say was caused by the dangerous driving of the person at the wheel of the stolen vehicle.

The doctor had parked at Ellerslie Racecourse in Remuera and was walking to the ticket machine when "a big guy thrust a gun into his side and demanded his car keys and wallet", telling him "we'll come back and get your family" if police were called, the doctor's shaken colleague has told the Herald.

"He's a mess. He was terribly traumatised."

Police confirmed a man's car was stolen at gunpoint in Ascot Ave just after 2pm yesterday, with the vehicle later involved in a crash that moderately injured another motorist before police located it in Grey Lynn about 6pm.

"[The police helicopter] Eagle monitored the car, which was being driven at high speed until it stopped in Bannerman Rd, Western Springs. The three occupants were immediately taken into custody."

It was after the trio was arrested that police became aware an earlier crash on Great North Rd had been "caused by the dangerous driving of the stolen car", police said.

A 27-year-old man has been charged with aggravated robbery, dangerous driving and failing to stop to ascertain injury and would appear in the Auckland District Court today.

A 20-year-old woman has also been charged with aggravated robbery and will appear in Auckland District Court on Wednesday next week.

"As the matter is now before the courts, police have no further comment."

The doctor's colleague contacted the Herald because she was upset the public hadn't been told about the incident. She didn't know what kind of gun was used.

The doctor believed he was followed to the carpark after stopping at a nearby petrol station.

She didn't want to be identified, but wanted the public to be aware "[violent crime] can happen anywhere", the woman said.

"It's terrifying. This doesn't feel like New Zealand anymore."