David Bain will appeal against a High Court ruling banning him from accessing key documents relating to his compensation claim.
Mr Bain spent 13 years in prison for murdering his parents and three siblings in Dunedin in 1994 but was acquitted on retrial in 2009.
His legal team wants access to 250 documents Justice Minister Judith Collins received around the time she decided to get a report on his claim reviewed.
Crown lawyers argued the documents are privileged and the High Court last month agreed.
Justice Keane says Ms Collins complied with her duty and is legally entitled to withhold key documents from the case.
Mr Bain's lawyers say they will lodge an appeal against that decision at the Court of Appeal in the coming weeks.