The panicked screams of two young children as they desperately clung to their father on top of a slowly sinking car near Hastings will forever be etched in Duane Awa's mind.

He was travelling down Ruahapia Rd from work when the sight of an empty car half-parked on the road and a woman standing 10 metres down the bank sparked his interest.

"I knew straight away ... I actually saw the fence had been busted and that's when my heart started racing and I knew exactly what was going on - a car had gone off the road and into the Karamu Stream," Awa said, nearly 48 hours after the ordeal.

And before he knew it, he had stripped down and jumped in.

Barely before he had thought about what he was doing, Duane Awa had stripped off and leapt to the rescue. Photo / Warren Buckland

"It was that cry, that scream that really got me. It hit the heart, eh. That was enough for me to do what I had to do and jump."

As he was swimming to the car, all he could think of was the two girls, who he believed were about 3 and 5. And it wasn't until he got closer that he saw the youngest was still half-trapped in the vehicle.

"It happened so quickly that I believe the father was ready to go and retrieve the second but he was held up with the elder girl, so I was able to jump in and grab her through the back window and put her on to the roof.

"You could see it in their eyes. They were so scared. I had to try my hardest to calm them down cause [the father] was shocked. I told them 'everything is going to be okay'."

The arrival of three men helped them lift the two girls up a fair way on to the railway bridge, while the father climbed up the panel and Awa did the same.

However, the hero does not believe he could have done what he did this time last year, when weight issues meant he struggled to breathe.

"It is amazing what the body can do when it is under that sort of pressure."

In that time, he has been training every day and has lost more than 20kg.

But things took a strange turn when emergency services arrived and they did not know where the family had gone.

"Something just wasn't right but at the end of the day, my main focus was on the two young girls and getting them to safety, which we had done."

It was believed they had driven to the hospital, but when Awa arrived at Hawke's Bay Hospital to get checked himself for a suspected rib injury, no one had seen the family.

Baker said things were still "a little grey".

"The issue we have got is that all three have left the scene in a third vehicle which turned up and inquiries are still ongoing to locate those people.

Trade Towage owner Steve Karatau watches the car get winched from the Karamu stream near the railway bridge by Ruahapia Rd. Photo / Warren Buckland

"We have made some inquiries at the local addresses and we believe we know who it is but we are yet to speak to them."

However, he had admiration for Awa: "As far as the Police goes, it is quite heroic what he has done to save this family. It had potential to be a lot worse and could have easily resulted in a fatality."

Baker understood the car had failed to take an intersection and had driven straight through a fence, ending up in the stream.