An "idiot" speeding driver who crashed at 200km/h and killed his new partner was today jailed for nearly three years.

Jaimey Leigh Fellows, 32, died when her partner of three months, Craig Richard Bennett, lost control at high speed on State Highway 1, near Burnham, 30km south of Christchurch, in the early hours of October 21 last year.

Bennett, a 36-year-old electrical technician from Dunsandel, earlier admitted a charge of dangerous driving causing her death.

Jaimey Fellows died in a fatal car crash outside Christchurch on October 21 last year. Photo / Facebook

Fellows' parents gave emotional victim impact statements at Christchurch District Court this afternoon.

Her proud father Johnathan Fellows spoke of struggling to come to terms with the loss of a beautiful daughter after the "actions of an idiot".

"What more is there to lose than your own child?" he said.

"This kind of thing guts you hollow."

He questioned the "insane velocity" and whether it should be called an accident, giving the analogy of loading a gun and pulling the trigger.

While her mother Michelle Edwards accepted it was a tragic accident, and that she forgives Bennett, she has been profoundly affected by the loss of her "beautiful, intelligent, funny and kind" daughter.

She described the 200km/h-plus speed as "horrendous, extreme, reckless, and dangerous", which resulted in a "death trap".

"Craig made a terrible mistake driving at that speed," Edwards said.

"I would rather serve a jail sentence any day than lose a child."

Witnessing the 200m crash trail was "absolutely traumatising", describing it as looking like a plane crash site.

Crown prosecutor Sean Mallett noted Bennett's 2008 conviction for an unnecessary exhibition of speed, a racing-type offence, as well as seven speeding infringements over the last 12 years, which showed Bennett had a "persistent disregard" for driving within the speed limit.

The court heard how the couple were travelling in Bennett's Nissan south of Rolleston when he started picking up speed.

Craig Bennett was doing 200km/h when he lost control and crashed outside Christchurch in October 2017, killing his partner Jaimey Fellows. Photo / via Facebook

He overtook a delivery truck on double lines and sped past another car on a passing lane near Burnham Military Camp.

But as he attempted to exit the passing lane, he lost control. Crash investigators found Bennett was doing between 200-204km/h.

Police prosecutor sergeant Paul Scott said Bennett couldn't regain control as the car crossed the centreline.

The passenger door smashed through a fencepost and the car began to barrel-roll, the court heard.

Fellows' seatbelt snapped and she was ejected in the final barrel-roll as the car came to rest near the railway track, some 200m from where the crash began.

She died as a direct result of high-energy impact injuries to her chest, abdomen and limbs, the court heard.

Bennett later tested positive for THC, the active constituent for the drug cannabis. He told police he'd smoked a joint about 12 hours before the crash. There was no alcohol involved.

Defence counsel Andrew McCormick said Bennett is a "broken man - both physically and mentally".

The accident has had a "terrible impact" on both him and his family, McCormick said.

He accepts full responsibility for the crash, his lawyer said, and apologises profusely to Fellows' family.

Judge Brian Callaghan couldn't find a similar case where a death-crash driver had been doing such high speeds.

It was not an isolated piece of bad driving, Judge Callaghan said, with 7km of dangerous driving that night at "astronomically high" speed, and Fellows' death was the "end result".

Bennett was jailed for two years, eight months and ordered to make an immediate emotional harm payment of $10,000 to Fellows' parents. He was also disqualified from driving for four years.