A man had to make the terrible choice of rescuing his wife or teenage son when their car plunged into a river at the weekend.

Stacey Horton saved his wife, Vanessa, and their 13-year-old son Silva drowned in the Whanganui River.

Mid-Central police communications manager Kim Perks said today it was a very tough call for Mr Horton. "I would certainly not have wanted to be in his shoes."

Mrs Horton, 35, was driving Silva, his best friend, Robert Palmer, 14, and the family dog when her Mazda MPV stationwagon went off Somme Parade in Wanganui and plunged down a steep 10-metre bank into the water on Saturday.

Mr Horton said he arrived at the crash scene, less than two minutes after the accident happened to hear his wife screaming in the darkness and to see Robert and the dog scrambling up the bank.

He tried to dive down to their vehicle, which was nose down, more than a metre beneath the surface, he told The Dominion Post.

"I tried to get down and get him but I couldn't, it was just too deep. And Vanessa was going under," Mr Horton told the newspaper.

"I made a call to pull my wife to safety. I looked back and I could see the tail-lights but it was too far and I couldn't get him.

"I just had to accept the fact that he had gone.

"Instead of going down and risking my life as well as my wife and son's, I chose to take V back and sat on the shore praying. It was all I could do."

Police and fire officers were also unsuccessful in rescuing the boy.

"It was an incredibly traumatic incident for everyone involved," Sergeant Andrew McDonald of Wanganui police said.

"Police officers in uniform were diving in to try to reach the boy and fire officers were doing the same trying to hook a rope around the vehicle to pull it within easier reach.

"At the same we had staff trying to comfort his distraught family on the river bank."

Two local divers eventually reached the vehicle, which had sunk in about 4.5 metres of water, but it was too late to save Silva, Mr McDonald said.

The boy's mother and friend were treated for shock and minor injuries and had since been discharged from hospital.

Wanganui senior station officer Gary Wilson said the water was dark and murky and the firefighters struggled to reach the car.

"We tried everything but to no avail. It was a longshot but it was worth the risk to try and save him."

Divers recovered Silva's body early yesterday. His funeral will be held in Taihape.

Police said that alcohol and speed were not factors in the crash which occurred when the vehicle apparently skidded on wet grass. Silva Horton was one of three reported deaths on the country's roads during the weekend.

A 47-year-old woman died after her car rolled and caught fire on straight piece of road in Kirwee, 37km west of Christchurch, about 4am yesterday.

Police said the car was ablaze when emergency services arrived.

The woman, from Kirwee, was the only person in the car, said Constable David Pitkethley of Darfield police.

It was not known whether she was killed in the crash or by the fire.

Another person was killed in a two-car crash on SH33 at Okere Falls, 20km northeast of Rotorua, about 5pm on Saturday.

It appeared the driver of a Mitsubishi Colt lost control on a corner and crossed the centre line, colliding with a Mazda Proceed 4WD towing a boat, police said.

The driver of the Mitsubishi, the sole occupant, died at the scene.

Two adults and two children in the other vehicle were taken to hospital with moderate injuries.

SeanT21:

Its not fair to cut the little boy life short. Who knows what God has in store for him.