A jury will now begin its deliberations over whether a 20-year-old Hamilton man and his passenger are guilty of illegally racing a car which crashed, killing all four of its occupants.

Dylan Cossey and Stephen John Jones, both 20, have pleaded not guilty in the High Court at Hamilton to four charges of manslaughter by means of illegally racing and causing the four victims' deaths.

The pair also face a charge of operating a motor vehicle in a race or unnecessary exhibition of speed causing injury and failing to stop.

Jones faces an additional charge of attempting to pervert the course of justice at Hamilton on June 28, 2016, after allegedly editing and shortening a film he took as the crash happened.

Lawyers for the pair issued their closing statements on Friday, while Justice Anne Hinton this morning issued her closing submission.

She urged the jury to put aside any prejudice they had about young men who "drove far too fast" and instead base their verdicts on the facts surrounding the case.

"You just need to assess the evidence collectively in a way that makes sense to you."

She explained that although six of the seven charges were jointly laid, they were materially different for each accused.

For the manslaughter charge to be proven in Cossey's case, the jury had to be sure that he was not only operating a motor vehicle on a road in a race with Robinson but that he caused the death by operating a vehicle in that race.

She went over key parts of witness evidence, including from drivers of vehicles which were overtaken prior to the crash.

She reminded them of one witness who said he was overtaking a vehicle when Cossey's Honda and Robinson's Nissan passed him in the southbound lane, with the Honda going past first.

The judge reminded the jury of Cossey's defence with counsel Philip Morgan QC stating that it was only what was happening immediately prior to the crash that mattered.

He submitted his client was changing down gears while Robinson's car passed his with ease.

Boot had agreed that it was Robinson's driving which caused the deaths of all victims.

A key aspect of Jones' guilt was whether the jury was satisfied that his filming Cossey as he drove in the short period prior to the crash encouraged him to go faster, she told the jury.

Another aspect was whether him yelling "gap it bro, gap it bro" immediately after the crash encouraged him to flee the scene without stopping to render assistance.

Boot said if his client was wanting to impede the police investigation he could have just deleted it.

Hamilton woman Hannah Leis Strickett-Craze, 24, Paul De Silva, 20, and Lance Robinson, 28, both of Te Awamutu, and Jason McCormick Ross, 19, of Stratford, were all killed instantly in the crash on June 24, 2016, when it collided with a van, badly injuring the driver. He also gave evidence, but his name was suppressed.

The crash happened on Ohaupo Rd, at the intersection of Ingram Rd, outside Hamilton Airport, on June 24, 2016, when Robinson lost control of his northbound Nissan Skyline and collided with the southbound van.

Cossey's lawyer Phil Morgan QC earlier told the jury the unquestionable issue was the fact Robinson drove "dangerously or recklessly and that he caused the deaths of the deceased".

"But it's stretching the law too far to say it's Mr Cossey who is guilty of manslaughter."

Jones' lawyer Russell Boot submitted on Friday that his client was "merely a passenger in the car" and did nothing more than film the Skyline's overtaking manoeuvre and then give it to police to help them.

Boot said the blame for deaths lay at the feet of Robinson, who was driving with alcohol, methamphetamine and cannabis in his system.

The jury, of five men and seven women, were sent out to deliberate at 1.35pm.