The Supreme Court has granted David Bain leave to appeal to it regarding a pre-trial application.
David Bain is due to stand trial next week over the murder of five family members in 1994.
The Supreme Court appeal will be heard on Wednesday.
Meanwhile, a decision is also pending from the High Court in Christchurch on an application for a stay of proceedings.
If that is granted, Mr Bain's trial would not go ahead.
