A former prison guard who was found guilty of sexually abusing 10 inmates, including a pregnant woman, at a Sydney jail will remain behind bars after the state's highest court turned down his appeal.
Wayne Gregory Astill was sentenced to 23 years in prison after he was convicted of 34 charges, including aggravated sexual assault and indecent assault.
He was found guilty of 27 charges related to non-consensual conduct but admitted to seven counts of misconduct in office related to inappropriate consensual sexual acts.
The jury found he sexually assaulted 10 prisoners, one of whom was pregnant at the time, while he was stationed at Dillwynia Correctional Centre in northwestern Sydney.
Earlier this year, he took his case to the Court of Criminal Appeal to appeal his convictions and sentence.
His barrister Tomislav Bicanic argued the trial judge, District Court Judge Gina O'Rourke, had erred when she gave a direction to the jury about 'tendency' evidence.
During the trial, the Crown prosecutor argued the evidence demonstrated Astill had a tendency to make sexually suggestive comments, put himself in a position where he was alone with women, and engage in sexual acts without consent.
Mr Bicanic argued the Crown had relied upon evidence that 'varied widely in terms of severity or seriousness' and conduct for which Astill was not charged.
He argued Judge O'Rourke should have given further direction to the jury about how they should think about the tendency evidence in order to avoid 'reasoning errors'.
However, during an appeals hearing in June, Crown prosecutor Elizabeth Nicholson said it wasn't necessary because the jury had been 'correctly directed' by Judge O'Rourke, who had 'made it abundantly clear' they must not find Astill guilty unless they found the victims' testimony proven beyond a reasonable doubt.
She argued the jurors were given clear instructions multiple times about the standard and onus of proof.
'The jury clearly understood those directions,' the Crown prosecutor said at the time.
'There cannot be a miscarriage (of justice or) a practical disadvantage to the applicant in circumstances where the jury is considering the same body of evidence.'
His appeal was heard by Chief Justice Anthony Bell and Justices Kristina Stern and Justice Richard Button earlier this year.
On Monday, the Court of Criminal Appeal handed down a unanimous 3-0 decision in which Astill was refused leave to hear his appeal against his conviction and sentence.
Astill will be eligible for release on parole in December 2037.