Proceedings are underway in the NSW Supreme Court for a class action seeking compensation for survivors and others impacted by the June 2023 Hunter Valley bus crash.

The class action is being led by Adam Bray, whose son Zach Bray died when a bus, driven by Brett Button, rolled at a roundabout near Greta.

Ten people were killed and 25 others were injured in the crash.

The class action is seeking compensation from Transport for NSW, the government body that provides and maintains roads and transport services in the state.

In a statement of claim lodged by Mr Bray and the class action group, it's argued the elliptical design of the roundabout, high-grown shrubbery around the area, and a lack of safety signage contributed to the crash and its severity.

The claim states the group's belief that there's "inadequate road warning signage of the hazards associated with the interchange, including its tightening radius".

It's also argued a signposted 80 kilometres per hour speed limit is not appropriate for the roundabout, with "no other change in speed limit or advisory speed sign for the interchange".

The claim argues Transport for NSW breached its duty of care owed to the plaintiff and the group members.

"The breaches particularlised above were such that it gave rise to a real and significant risk that a driver of a heavy vehicle …that entered the interchange and was exercising reasonable care … could nonetheless lose control of the vehicle," the document said.

The group is seeking compensation for survivors, and others who suffered "mental harm" due to the crash.

In this morning's brief hearing, Transport for NSW's lawyer Brian Maroney was asked by Justice Peter Garling if his client intended to file a claim of its own.

"Is it the defence's proposal to cross-claim against the owner of the bus?" he said.

"I suspect that is highly likely," Mr Maroney said.

Mr Maroney was also asked why he had sought an additional six weeks to file a defence.

He told the court there was a "lot of material" that he had not received on issues central to the case.

Mr Maroney said there were some documents outstanding, including roundabout designs, and information regarding signage and sight-lines.

"I expect there to be quite a bit of material, your honour," he said.

Justice Garling said that due to the upcoming holidays, the matter would return to court on February 7, 2025.

The driver of the bus, Brett Button, pleaded guilty to several charges relating to the crash, and was sentenced last month to 32 years in jail in September.

Button and his legal team have since lodged a notice of intention to appeal the sentence.