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The truck driver whose life was saved by an heroic Opotiki teenager has written to saying the young man should be given a bravery award.

Paul Clark's 23-tonne truck and trailer unit was perilously close to sliding into the Waioeka River after an accident in the Waioeka Gorge, south of Opotiki, on Sunday night.

Eighteen-year-old local Peter Hanne was hailed a hero by police after risking his own life to save Mr Clark.

Speaking for the first time, the British man, who has only been in New Zealand seven months, said he couldn't thank Mr Hanne enough.

"I was injured and trapped and this young lad appeared from nowhere," Mr Clark wrote.

"He had the confidence of an experienced rescuer, giving no thought for his own life to rescue me.

"If my truck had of gone, he would have gone with me!"

Opotiki police Senior Constable Doug Henry said, after coming upon the accident, Mr Hanne "went and got a wheel brace, crawled into the wreckage and up to the driver's window, smashed the window and got the driver out and up to the bank."

Mr Clark said he was lucky to be alive.

"I cannot thank him or praise him enough as without his help who knows what may have been!

"If there is a bravery awards scheme in NZ I would like to personally nominate him.

"I cannot thank him enough and also his Mum for the blanket and tea!"

But earlier Mr Hanne said he was only doing what needed to be done, when the truck crashed just a few hundred metres from his house.

"We got a knock on the door, and there was a guy who said there's a truck in the river," Mr Hanne said.

"I just said to my family: 'Call the cops' and ran out.

"I didn't even remember to put my shoes on."

When he arrived at the accident he found the truck had jack-knifed over the edge of the road so that the trailer was leaning at a 45-degree angle over the river, with the cab of the truck dangling underneath it.

"I knew the normal thing to do was call the fire brigade and wait - but I heard it creaking and I knew we needed to get him out pretty quick.

"At one point it was creaking so much he [Mr Clark] was saying: 'It's going to go over - it's going to go.'

"But I didn't feel fear - there was too much adrenaline pumping."