Driver denies opioid 'influence' on fatal bus trip

A wedding bus driver convicted over one of Australia's worst crashes has appealed against his "manifestly excessive" jail sentence of 32 years.

Brett Andrew Button, 60, had been driving too fast and engaged in risk-taking behaviour before the crash, which killed 10 and injured 25 people, in the NSW Hunter Valley in June 2023.

While dependent on opioid painkiller Tramadol, he has denied he was affected by the drug when he lost control of the vehicle.

He was sentenced in September to a maximum jail term of 32 years with a non-parole period of 24 years.

District Court Judge Roy Ellis said he was unaware of any other case that had such a devastating impact on so many people.

The vehicle - which was carrying guests from a wine estate wedding - entered a roundabout on the way to Singleton before tipping over and hitting a guardrail.

Button has challenged his sentence in a bid to reduce his time behind bars, which was briefly heard in the NSW Court of Criminal Appeal on Thursday.

He claims Judge Ellis was wrong to find he was driving under the influence of Tramadol at the time of the accident.

He also contests a finding the speed required to tip the bus over was only 31km/h.

Button entered the roundabout at an estimated 52km/h before accelerating to about 56km/h, the District Court was earlier told.

"In all of the circumstances, the aggregate sentence of 32 years with a non-parole period of 24 years was manifestly excessive," his grounds of appeal read.

A hearing has been scheduled for October 3.

Prosecutors expect voluminous evidence to be tendered, including victim impact statements from the families of those who died or were injured in the crash.

A psychological report for Button and several references attesting to his good character will be considered by the court.

The bus driver will not appeal against his conviction.

Prosecutors dropped 10 counts of manslaughter as part of a plea deal.

Button pleaded guilty to 10 charges of dangerous driving causing death, nine counts of driving causing grievous bodily harm and 16 counts of causing bodily harm by wanton driving.

A class action has been filed against the NSW government over the roundabout's design by those injured and family members of the dead.

The speed limit through the interchange was allegedly too high.