The man who stabbed an Auckland couple to death and caused a third person's non-fatal injuries has been found not guilty by reason of insanity. 

Justice Sally Fitzgerald issued the ruling at the High Court at Auckland this morning after both the Crown and defence lawyer Shane Cassidy reached the same conclusion based on two psychological reports. 

"I agree with counsel it is abundantly clear the only reasonable verdict in this case would be not guilty by reason of insanity," Fitzgerald said. 

She approved Cassidy's request that interim name suppression remain in place until he discusses with his client the possibility of pursuing permanent name suppression. 

Herman and Elizabeth Bangera died on March 19 last year. Police found the couple critically hurt at their Epsom home. Both died a short time later at the scene - an incident that Detective Inspector Scott Beard described at the time as an "absolute tragedy". 

A third victim as well as the defendant were also discovered at the house - both also wounded. They were both taken to Auckland City Hospital, with the defendant going into police custody as soon as he was discharged. 

Herman Bangera, 60, had been a volunteer at Child Evangelism Fellowship. Organisation director Pamela Brooking described him last year as a "lovely man and wonderful dad". His family, she said, was the "epitome of what family is". 

Elizabeth Bangera, 55, worked at the University of Auckland. A university spokesperson described her as a "highly respected colleague and friend". 

The couple moved into their Epsom flat around 2007, after immigrating to New Zealand from India, because of the school zone there, a neighbour and friend of the couple previously told the Herald. 

The defendant pleaded not guilty by reason of insanity last June, but an agreement from both sides wasn't confirmed until today. He had been set to go to trial next month for two counts of murder and one count of attempted murder. 

Instead, he will remain at the Mason Clinic until a disposition hearing in June to determine if he should remain at the lockdown psychiatric facility. 

The man was not present at today's hearing.