A man who beat and stabbed a Dunedin couple to death, then set fire to their house in 2018, has finally admitted the double murder

The Otago Daily Times reports it took three-and-a-half-years for Wiremu Namana to plead guilty to killing David Clarke and Anastasia Margaret.

Namana, who is a morphine addict understood to have been going through withdrawal, went to the victims' home to source more drugs.

Crown Prosecutor Robin Bates says he flew into a rage, before using a sledge hammer, cricket bat, and a knife to critically injure the pair.

He'll be sentenced in August.