The lawyer of a man accused of murdering his wife more than 37 years ago in the northern NSW town of Walgett says his client denies the charge against him and will likely fight the allegation in a trial.

Almost four decades after wife Roxlyn disappeared, John Bowie on Sunday faced Parramatta Bail Court charged with her murder.

The 69-year-old denies killing Ms Bowie, who vanished from her Walgett home on June 5, 1982. Her body has never been found.

Bowie did not apply for bail at court on Sunday and it was formally refused.

He's scheduled to next appear before Central Local Court on December 2.

Lawyer Sam Karnib told reporters outside court on Sunday that his client denied murdering his former wife and would contest the accusation.

He would likely make a bail application at his next court appearance.

"He's strongly distressed by the allegations put before him and put before the court. Apart from that, he's obviously going to defend this matter - it's a matter that's going to proceed to trial," Mr Karnib said.

Bowie was on Friday arrested at Queensland's Woodford Correctional Centre and on Saturday morning extradited to NSW.

"I don't even know if she's dead or not," Bowie told reporters as detectives escorted him through Sydney Airport en route to Surry Hills Police Station.

A coroner in 2014 found Ms Bowie was dead but couldn't determine the cause of death or the location of her body. A $1 million reward for information leading to the discovery of Ms Bowie remains in place.

Police admit the case against Bowie is circumstantial.

New interviews with witnesses and technical advances in uncovering forensic evidence have helped progress the case.

"It's happened before, we know the road ahead will be challenging," Detective Superintendent Danny Doherty told reporters on Saturday.

Det Supt Doherty said personal items uncovered during a 2018 forensic search for Ms Bowie near a Walgett home would play a role in the prosecution.

In a separate search in April, police found a silver ring with the letter "R" and black and gold packaging for a Swann-Morton surgical blade.

Police have declined to outline a motive for Bowie's alleged actions, saying it would be revealed in court proceedings.