Family members of one of the four victims show their dismay outside court following the sentencing of Dylan Cossey to 12 months' home detention after being found guilty on four counts of manslaughter.

Family and friends of four people killed in a crash caused in part by a 20-year-old Hamilton man are outraged he's not going to prison.

"Well, that's a f...ing joke," someone in the public gallery exclaimed as Dylan Cossey was sentenced to 12 months' home detention, 400 hours of community work and disqualified from driving for seven years.

Cossey, who had been found guilty by a High Court jury in Hamilton in February on four counts of manslaughter, was sentenced in the same court on Friday.

TOM LEE/STUFF Dylan Cossey arrives at the High Court in Hamilton for sentencing after being found guilty on four counts of manslaughter.

He had fled from the scene of a head-on smash near Hamilton Airport on the night of June 24, 2016, with his co-defendant Stephen John Jones, 20, in the front passenger seat.

Cossey was racing his Honda Integra against a Nissan Skyline at estimated speeds of more than 150kmh.

The race came to a sudden end when the Nissan lost control and collided with an oncoming van about 10pm. In the doomed vehicle were Hannah Leis Strickett-Craze, 24, Lance Tyrone Robinson, 28, and Paul de Silva, 20, all from Waipa, and Jason McCormick Ross, 19, from Taranaki.

TOM LEE/STUFF Narissa Ryan, Paul de Silva's girlfriend, left, with his aunt Amber de Silva expressed their dismay at Dylan Cossey's sentence outside the High Court in Hamilton.

Cossey was found guilty of the manslaughter charges while Jones was found not guilty on all four manslaughter charges.

Both Cossey and Jones were also charged with causing injury to the van's driver and failing to stop to ascertain injury. The van driver suffered multiple leg fractures and had to be cut from his vehicle. Cossey was found guilty of this also, while Jones was found not guilty. Both were guilty of the failing-to-stop charges.

Jones was also found guilty of one count of attempting to pervert the course of justice - a charge that relates to his editing of the video he took of the crash and the moments leading up to and after it, removing 20 seconds of evidence before handing his phone in to police.

CHRISTEL YARDLEY/STUFF Stephen John Jones is pictured arriving at the High Court in Hamilton before the start of his trial.

Cossey's sentence was evidently more lenient than many expected.

"I think it's a joke. Cossey's behaviour has not shown any remorse or any regard for the event. It does not show a hard line for street racing and I think it should have been tougher," said Amber de Silva, the aunt of Paul de Silva, outside court.

Cossey would still have luxuries such as Sky TV, home-delivered meals and hot showers as he served his sentence, she said.

GEORGE HEARD/FAIRFAX NZ The Nissan Skyline the four victims were in was ripped apart in the crash on the night of June 24, 2016.

Crown prosecutor Duncan McWilliam had sought a starting point for Cossey's sentence of eight to nine years in prison. Cossey's counsel Philip Morgan QC urged a three-year starting point - and it was this recommendation that Justice Anne Hinton went with.

A deduction for youth, remorse and prospects of rehabilitation knocked 12 months off, and the judge converted the two-year jail sentence to 12 months of home detention.

Such a sentence was not a soft option, Justice Hinton said.

"Imprisonment would not be in your interests or in the public's interests."

It would be inappropriate to classify Cossey as being at high risk of reoffending - even though he had offended while on bail on the manslaughter charges, she said.

He had been convicted and discharged on a charge of careless driving, laid because he had fallen asleep at the wheel while driving.

Cossey was prone to "impulsive, stupid and rash decision-making", she said.

"You were an immature, naive 18 year old.

"The behaviour that underlies your offending is a tragic hallmark of youth."

While Cossey's guilty verdicts meant his actions were "a substantive and operative cause of death" of those killed, they were not the only cause, or the primary one.

That was the driving of Lance Robinson, who was behind the wheel of the Skyline when it crashed. A post-mortem found him to be three times the legal driving limit for alcohol, and with traces of cannabis and methamphetamine in his bloodstream.

Before the trial began, Cossey had displayed erratic behaviour and had spent 17 days in the Henry Bennett Centre, Waikato Hospital's mental health unit, as a result.

"I accept that you are remorseful, although you have a strange way of showing it," said the judge.

Prior to sentencing, numerous family members of the four who died delivered their victim statements to the court.

"The police notification took my breath away, and I am not sure I have got that breath back," said Phoebe Howarth, the mother of Robinson.

"It was all avoidable and such a waste ... I fear Mr Cossey has no recognisance of his actions and unless he can learn to become a better citizen, he will be a danger to society."

Paul Craze, the father of Hannah Leis Strickett-Craze, spoke of how he learned of his daughter's death as he was browsing internet news sites and saw her face.

His initial dismay and numbness gave way to anger at the two men who "fled like cowards, thinking only of themselves" and later "lied and colluded to manufacture a story."

Jones's day of judgment was delayed: His sentencing was adjourned to May 3, because the Probation Service had not had time to assess whether his home was suitable for either home or community detention.