Accused NSW killer truckie makes bail bid

An overweight truck driver charged over the deaths of a young couple in a seven-vehicle pile-up needs to be released on bail so his possible sleep apnoea can be assessed, a Sydney court has been told.

Robert Crockford is facing more than a dozen charges after his semi-trailer ploughed into six vehicles stopped at roadworks on the Newell Highway north of Dubbo in January.

Reagen Skinner and his 19-year-old girlfriend, Hannah Ferguson, were killed and 10 others - including a two-year-old girl - were injured in the crash.

Crockford's barrister, Jack Tyler-Stott, told the Supreme Court on Thursday the truckie needed to be clinically assessed for sleep apnoea as it may form part of his defence.

He claimed, based on a doctor's assessment, that any sleep disorder couldn't be properly understood unless Crockford's health improved.

His treatment in custody had been adequate but not as good as what Crockford could receive out of jail, the lawyer said.

Crockford suffered leg fractures and internal injuries in the crash. He has a history of weight issues.

"There is some biology that needs to be explored," Mr Tyler-Stott said.

But prosecutors said Crockford's treatment in custody had involved trips to see an orthopaedic surgeon at the Prince of Wales Hospital in Randwick.

It was argued tests could be conducted for sleep apnoea in custody.

The Crown says potential sleep apnoea is the defence's third attempt to explain what caused the crash.

Crockford told paramedics and a doctor his brakes had jammed and that he'd also lost consciousness before later claiming he'd had a coughing fit, the court was told.

"It is just to raise version number three of why he failed to brake," the Crown suggested.

Prosecutors allege the truck slowed from over 100 km/h to 80 to 90 km/h on approach to the roadworks "but there was no slowing after that".

It allegedly slammed into the first stopped vehicle at 86 km/h.

Acting Justice Peter Hidden reserved his decision until Friday morning.