Mr McVicar said he was travelling about 100km/h when the crash happened.
"It was dark and drizzling. There was traffic coming towards me and all of a sudden one car pulled out of that traffic and was coming towards me. It looked like he was passing," he told the Weekend Herald.
"There wasn't enough room for all of us on the road, so I moved over. There was a cyclist alongside me on my left so I couldn't move over too far without bowling her.
"I was concentrating on not hitting the cyclist and then next minute there was a thump."
Mr Hewat allegedly went to turn right down a side road when the cars collided.
"He turned into my driver's door and shunted me off the road. I was busy trying to dodge a concrete power pole.
"I was spinning out of control by that stage ... I spun around and hit a wooden pole on the other side of the road and broke that and brought the wires down."
He had only just passed the cyclist, Colette Cregan, who had been working in a Napier cafe.
Mr McVicar was able to get out of his car, which was written off, to see if anyone was injured.
"I rushed over to the other guy's car and he was gone. I looked around and there was a person sitting on the grass. That turned out to be the cyclist. I asked her if she knew where the other person was and she said, 'Yeah, he's ... down the road."'
A group of men caught up in the crash when a powerline landed on their van offered to drive Mr McVicar to find Mr Hewat.
They soon spotted him down a side road and Mr McVicar approached him.
"I said, 'Are you okay? Were you driving that car back there?' and he said yes. I said, 'Look, you better come back because there's power wires down and we don't know if anyone's hurt."'
Mr Hewat identified himself and handed over his business card.
Police said an investigation was continuing. They refused to speculate on the cause of the accident.
A spokeswoman said no decision had been made regarding charges.
Ms Cregan, 30, said: "It was quite shocking, I got a bit of a fright, I just couldn't believe what nearly happened."
She added: "I just saw the car coming towards me ... then I saw it crash into the other one. I went left and just biked as fast as I could, jumped off the bike and ran into the grass. Then I saw the lines go down and I just ran."
Ms Cregan, who is Irish and due to leave New Zealand in two weeks after a working holiday, said after the crash Mr Hewat came up and asked her if she was okay. He then asked for directions before walking away.
She left before speaking to police as she was shaken.
"I probably should have stayed ... but I just couldn't believe it happened. I was very, very lucky."
