Former Elgin businessman Nat Fraser had his appeal bid dismissed earlier this month by judge Lady Dorrian as a potential waste of court time.
However, three judges have now reviewed her decision and said the case should be decided at a full hearing of the Court of Criminal Appeal in Edinburgh.
Fraser has twice been found guilty of hiring a hit-man to murder Arlene, 33, who has not been seen since she went missing from her home in Elgin in April 1998.
He was first convicted of killing the mother of two in January 2003.
The Court of Criminal Appeal in Edinburgh confirmed his conviction, but Fraser then went to the UK Supreme Court, which ruled he had suffered a miscarriage of justice.
This prompted a second trial this year, at which he was again found guilty and jailed by judge Lord Bracadale for at least 17 years for the pre-meditated murder.
No date has yet been set for his next court hearing.