A Hamilton woman who shot her flatmate in a drug and alcohol induced haze has been jailed for what a judge called a "spontaneous moment of stupidity".

Tiffani Jade Sutcliffe, 23, was sentenced to three years and one month jail by Justice Christian Whata in the High Court in Hamilton on Thursday morning.

She earlier pleaded guilty to a charge of the manslaughter of Rhys Gordon Williamson by reckless discharge of a firearm.

DOMINIC ZAPATA/FAIRFAX NZ The Seddon St flat.

It was the evening of Tuesday, May 30, when Sutcliffe and her 20-year-old girlfriend had been drinking bourbons for most of that day in the Seddon St house when Williamson returned home from work late in the afternoon.

Williamson and Sutcliffe had known each other since she was nine years old, and were good friends and flatmates.

Sometime shortly after 6pm another man - Anthony Brett Clegg, 40 - arrived. He had obtained a gun from an associate, along with a metal box containing shells.

Members of the group then consumed GHB - gamma-hydroxybutyrate before Sutcliffe, her girlfriend and Clegg adjourned to a bedroom, with the intention of having group sex.

Williamson entered the room holding a single-barrel, top break 12-gauge shotgun, which he and Sutcliffe began playing with.

She took the weapon from him pointed it directly at him, asking if it was loaded.

Then she pulled the trigger.

Two metres away, Williamson, 40, took the full blast in the side of his chest, under his armpit.

He uttered the answer, "of course it's loaded, you stupid s***" before collapsing to the ground. He died shortly afterwards.

Sutcliffe's girlfriend fled from the room and hid in a bathroom for a time, before Sutcliffe asked her to drive Clegg from the house to an unknown location.

After Williamson was shot, Sutcliffe wrapped the gun in a towel and concealed under a bush near the driveway outside the house and dragged Williamson's body to the front step before calling 111.

Judge Whata said Sutcliffe was not forthcoming with the truth and told officers the weapon was a makeshift pipe fashioned into a firearm. It had discharged after the end of the pipe had been tapped with a hammer.

Clegg was later jailed for two years for unlawful possession of a firearm.

Six months has now gone by since Kath Brown lost her 40 year old son.

"As a mother you never expect to bury your child but to have someone so young, shot down in his prime is devastating and soul destroying," she told the courtroom on Thursday.

"It was a stupid and callous action that has changed our family forever."

Williamson had had his problems in the past, Brown said, but was working on turning his life around.

"The years spent raising Rhys watching him develop into a kind and loving man, helping him through trials and tribulations...then to lose him because of a stupid girl who did not have the sense to be careful with a firearm."

Williamson's estranged children would never get the chance to know their father, Brown said, because of a "callous and senseless act".

"What will I have to remember him by in my so-called golden years? A photo album of childhood photos, my memories, and a box of ashes.

"Cold comfort."

Brown's husband Mervyn, who was stepfather to Williamson for 30 years, questioned Sutcliffe's remorse, saying she merely wanted her "15-minutes of fame".

"I believe she deserves a sentence that realises the gravity of her offence, that makes her accept responsibility for taking a man's life."

In sentencing Justice Whata said Sutcliffe's actions were reckless with the highest level of consequence, but were less serious than previous cases where the defendant had sought out or loaded the gun themselves.

​ "Your actions were a spontaneous moment of stupidity."

He began with four years jail and gave discount for an earlier guilty plea and personal circumstances, which included a long history of substance abuse and the loss of a previous partner to suicide.

However, he added six months for Sutcliffe's attempt to conceal the evidence before making the call for help.

"You are now deeply aware of the significance of what you have done and the need to turn your life around. You're a prime candidate for rehabilitation," he said.

He sentenced to three years and one month, with no minimum non-parole period.