A man who unexpectedly pleaded guilty to murdering American mathematician Scott Johnson now "maintains his innocence", a Sydney court has heard, as a judge dismissed his bid to halt sentence proceedings.
Scott Phillip White, 51, is appealing after he entered the plea during a pre-trial hearing in January, despite previously denying responsibility.
He was charged with the murder in 2020, more than three decades after Mr Johnson's body was found at the base of cliffs at North Head, Manly, in 1988.
White's lawyers attempted to have the plea withdrawn by focusing on a potential "cognitive impairment", however the NSW Supreme Court convicted him of the murder.
The court on Tuesday heard an application to vacate his sentence proceedings as his lawyers argued the Court of Criminal Appeal (CCA) should first determine his appeal against conviction.
Senior Public Defender Belinda Rigg SC told the court it was "an unusual situation" involving "someone who is being sentenced who maintains their innocence in relation to the offence they're to be sentenced for".
The court heard while a notice of intention to appeal has been submitted, no grounds of appeal have yet been filed and the matter did not proceed on an "urgent" basis as was originally foreshadowed.
Justice Helen Wilson acknowledged if the CCA ultimately vacates the decision to accept the plea, the sentence proceedings would be deemed "futile".
But she agreed if the court were to wait until the full extent of the appeal process is exhausted, it could be "literally years" before the case is determined.
"That is not a delay which I think could ever be regarded as in the interests of justice and particularly not when this matter already has been the subject of decades of delay," the judge said.
"Not, of course, the fault of Mr White, but delay which nevertheless must inform the court's overall approach to this particular application."
The court heard Mr Johnson's family — including his brother, Steve Johnson — have paid about $US20,000 ($27,000) for non-refundable flights from the United States to attend the sentence.
In addition, relatives have been preparing victim-impact statements, which was described as "a most traumatic" process for them.
"To delay the matter would be, I think, bordering on the unconscionable, and I'm not prepared to delay it," Justice Wilson said.
Mr Johnson's death was considered by police to be a suicide for many years, however his family always believed he was the victim of a gay hate crime.
In a relentless pursuit of justice, Steve Johnson reportedly spent up to $1 million on an investigator to prove his death was the result of foul play.
White's sentence hearing is expected to proceed on May 2.
