Terrifying footage has emerged of a driver coming inches away from colliding with oncoming traffic during a dangerous overtaking manoeuvre south of Christchurch.

On Monday at 3.56pm, Stephen Carter and two work colleagues were travelling home to Oamaru from Christchurch along SH1 when suddenly a car was hurtling towards them on the wrong side of the road.

Going at speeds of 100km/h, the dangerous driver pulled out to try and overtake a number of vehicles including a truck.

Just inches away from colliding, the dangerous driver then moves onto the shoulder of the wrong side of the road.

Carter's driver slammed on his brakes, going from 99km/h to just 59km/h in a matter of a second.

Had his driver not acted so calmly and kept in his lane, Carter says they may have been dead.

"Not going to lie, my initial reaction was 'what the f**k is this f**king idiot doing?' There's no way he was going to get through there, especially with a truck still left to try and overtake," he told the Herald.

"We were lucky our driver stayed calm because we had nowhere to go.

"Had we gone right we would have been smacked up by the truck. If we had gone left then we would have gone into the car. We were lucky my mate kept his composure and the dipstick coming towards us realised there was a shoulder and headed further right.

"I couldn't believe it. I can't believe anyone can be so bloody stupid.

"It would have been carnage and Oamaru would have had three fewer residents returning home to their families."

Unfortunately, it wasn't the only incident with the dangerous driver.

Less than a kilometre down the road, Carter's partner was following behind and said the dangerous driver then came close to crashing into the truck after attempting to make another risky pass.

Carter says the driver continued along the outside and suddenly pulled straight across in front of the truck, coming close to colliding with the unsuspecting truckie.

"My missus was about 400 to 800 metres behind us and we checked her dashcam and we saw the same car trying to get past the big truck.

"Turns out he must have given it a bit of gas while on the shoulder of the wrong side of the road because he pulled straight across the road into the front of the truck driver.

"The truck driver wasn't even aware of the guy passing him before he was on the extreme right off the road. Then all of a sudden the truckie sees this guy swerve from the right-hand side and nearly takes him out. In his own words, he said he 'crapped himself'.

"We're lucky no one was hurt."

The incident has been reported to Oamaru Police, who are currently investigating.