Michael Atkins, who was acquitted of murdering his lover Matthew Leveson, must give evidence at a coronial inquest into the younger man's death in 2007, a NSW appeal judge has said.

Mr Atkins was the last person to see Mr Leveson alive, outside the Sydney nightclub Arq in September 2007.

Mr Leveson's body has never been found.

Mr Atkins was later acquitted of murder and manslaughter.

He exercised his right to silence during his trial in 2009 and is expected to give evidence about the matter for the first time.

Deputy State Coroner Elaine Truscott ordered Mr Atkins to address the inquest, and he appealed against the order in the Supreme Court.

In dismissing his case, Justice Lucy McCallum said:

"The right to silence is, of course, important. But so is the coroner's jurisdiction."

Under an order given by the coroner, Mr Atkins' evidence cannot be used against him in a criminal trial.

'We just want to bring Matt home'

Mr Leveson's mother, Faye Leveson, cried outside the Supreme Court and begged Atkins' family to encourage him to reveal anything he knew.

"It's our world, it's our family" she said.

"How do you tell your other two boys, how do you tell them you can't give them their brother back? It's just not fair."

Ms Leveson said she hoped the inquest would help the family locate her son's remains.

"We just want to bring Matt home. That's all we want," she said.

Mr Atkins will give evidence at the coronial inquest at Glebe Coroner's Court on October 31.