Convicted double-murderer Scott Watson trying to get released on bail in preparation for 2022 appeal

Convicted double-murderer Scott Watson is trying to get released on bail to prepare for his appeal next year.

He was found guilty in 1999 of murdering Olivia Hope and Ben Smart in the Marlborough Sounds. Their bodies have never been found.

Sentenced to life behind bars, Scott Watson has now spent 23 years in jail but he's hoping next year's appeal will see him freed.

In a virtual bail hearing on Friday, his lawyer told Justice Kos it could be Watson's last chance.

"Mr Watson is acutely aware this is likely to be his final opportunity to overturn convictions," Watson's lawyer, Nick Chisnall said.

The hearing will reconsider whether he killed Olivia Hope and Ben Smart after a New Year party at Furneaux Lodge in 1998.

It will focus on the two hairs discovered in Watson's yacht, alleged to be Olivia's, and whether testing of them was flawed.

Watson's been denied parole three times - partly because he refuses to admit guilt.

Having waited more than two decades for this hearing, he wants to get out of prison to help his lawyers fully prepare.

Watson's hearing will take place at the Court of Appeal in Wellington, likely in June next year. 

A decision on whether he is allowed out of prison to prepare for it will be released on Monday.