Loved ones of those who died in the Hunter Valley bus crash have told of their devastation and grief, in victim impact statements read to the Newcastle District Court today.

Bus driver Brett Andrew Button was in court to hear of the families and survivors' heartache, as his sentencing hearing got underway.

Button was behind the wheel of a coach full of guests returning from a wedding in the New South Wales Hunter Valley late on Sunday 11 June 2023, when it tipped and slid along a guard rail.

Ten people were killed, and 25 were injured.

The brother of Rebecca Mullen, one of the victims, spoke directly at Button while delivering a victim impact statement.

"You changed my life forever... here I am talking to you and you can't even look me in the the face. You're a coward," Lachlan Mullen said.

"Every time you pop another pill, please think 'I'm a terrible person' as you swallow.

Ms Mullen's father, Matthew Mullen, told the court about his daughter's life, achievements, budding career as a doctor, and her wedding which was being planned at the time.

"Life was good, wedding dates were set … I was so blessed," he said.

"Our lives were destroyed.

"Touching [your daughter's] cold arm in a morgue is something a father can't explain."

Families tell of ongoing trauma

The mother of Lynan Scott, who was killed alongside her husband Andrew, told the court of her emotional experience since.

"Every fibre of my body will not let go of this," Lindy Muldoon said.

A statement, read on behalf of victim Darcy Bulman's mother, spoke of the impact the crash had on their daily life.

They told the court one of their family members no longer drives, because they do not feel safe.

They also told the hearing they have not been able to return to their full-time employment, due to emotional trauma.

"I find it hard to sleep for more than a few hours at a time," they said.

They also spoke of their emotions surrounding Darcy's death.

Judge says hearings are 'unprecedented'

In May, 59-year-old Brett Andrew Button pleaded guilty to multiple counts of dangerous driving occasioning death, dangerous driving occasioning grievous bodily harm, driving furiously, and causing bodily harm to survivors.

Facts tendered to the court detail witness statements that Button was driving "too fast" and "hot", and that some urged him to slow down before the crash at Greta.

The judge presiding over the sentencing hearing said on Monday the proceedings were "unprecedented" in scale.

Up to 60 people are expected to give victim impact statements in the Newcastle District Court over three days, which Judge Roy Ellis said would be highly emotional.

"Never before have so many people been killed and injured in a single motor vehicle incident," he said.

"There will be times where people become emotional… and need to be comforted.

Judge Ellis noted family and loved ones of Brett Button were also in the court room.

He told victims and their families those people "are not here to demean your loss".

Judge Ellis also told the court the sentence, which will be delivered after victim impact statements, will be lengthy.

"Justice is what this sentence is about … justice for the offender and justice for the victims and their families."

Three days have been set aside for victim impact statements, submissions and judgement.