The mother of a young woman killed in Australia's worst road crash in two decades says the plea deal given to driver Brett Button has torn apart any progress the families had made in recovering from the tragedy.
Rebecca Mullen was one of 10 wedding guests killed when their coach slammed into a guard rail and rolled near Greta in the NSW Hunter Valley in June 2023.
Leanne Mullen said she had allowed police to leave her daughter's body on the bus for two days in the belief it would ensure a proper investigation to allow justice to be served.
Speaking under parliamentary privilege on Wednesday night, Upper Hunter MP Dave Layzell read a letter she had written.
"My daughter's body lay with her friends in the cold inside the bus against the concrete gutter and metal guardrail for close to 48 hours before she was moved," Ms Mullen said in the letter.
"I had a strong belief, a trust, that in sacrificing my rights as a mother to hold my daughter close to me as she left this earth, the police were gathering evidence that could be used to ensure justice was done.
"Sadly, it wasn't the case."
Ms Mullen and several other relatives of those killed in the crash say they feel let down by the legal system after manslaughter charges against Button were dropped on May 8.
The 59-year-old pleaded guilty to the lesser charges of 10 counts of dangerous driving causing death, nine of dangerous driving causing grievous bodily harm and 16 of furious driving causing bodily harm.
Families said they had been left "devastated" by the prosecution decision and felt as though their loved ones' deaths had been in vain.
"I've now lost my faith and trust in justice - the powerlessness of it all is crippling," Ms Mullen said.
"It has torn apart any progress that we've made recovering from this nightmare we find ourselves in."
Attorney-General Michael Daley has asked the Director of Public Prosecutions for a full briefing on the matter.
In a statement, the DPP said it "acknowledges that this is a very distressing time for the families and that some are disappointed by the decision".
"The decision was made after close and careful consideration of the evidence, in accordance with the Prosecution Guidelines and after ongoing consultation with the families of the victims," the statement said.
"We understand the concerns of the victims and the victims' families.
"While the ODPP takes into account their very important views, the final decision is a legal decision made by reference to many factors, including the evidence in the particular case."
Button will return to court on May 30 when a date for his sentencing will be fixed.
