Bus victim tells of 'world changed forever' post crash

Persistent mental and physical injuries along with everlasting grief have been detailed by victims of a horrific, deadly bus crash.

Ten mostly young wedding guests were killed and another 25 injured, when a bus driven by Brett Andrew Button rolled over at a roundabout in Greta in the NSW Hunter Valley in 2023.

Sentencing proceedings against the company that employed Button - Linq Buslines - and two of its directors are taking place in Gosford Local Court on Wednesday.

Tearful parents of Singleton woman Rebecca Mullen, who died in the crash, outlined continuing grief at losing their beloved daughter.

Ms Mullen had been offered a position as a rural GP and, with her fiance, had posted out wedding invites only days before she was killed

She was a caring and family-oriented woman sorely missed by many, the court was told.

"(Rebecca) wanted to care for and help the people of a community similar to that in which she had been raised," father Matthew Mullen said.

"Her funeral was a testament to how many lives she was able to touch in just 26 years," mother Leanne Mullen said in court.

Button is serving a 32-year prison sentence for his role in the crash, as he was under the influence of opioid painkiller Tramadol and driving too fast at the time.

Linq directors Christopher Terrence Fogg and Anthony John Royle pleaded guilty to workplace safety breaches by failing to uphold their duty of care, having employed Button in his compromised state.

Mr Mullen said the consequences for the driver were of little comfort to his grieving family.

"I cannot understand how systems and processes supposed to protect the passengers and Bec did not prevent (Button) getting behind the wheel," he said.

Two surviving crash victims gave emotional accounts of long-lasting physical and mental tolls the crash has taken.

Former L'Oreal executive Jason Junkeer spoke of how an acquired brain injury from the crash led to him losing the job of his dreams.