Police say a man who apparently killed himself during a standoff with police in Christchurch, New Zealand, had posed a "significant threat" to the community and supported the actions of the mosque gunman, although he didn't have a direct connection to him.

Police on Wednesday revealed details about the death last week of 54-year-old Artemiy Dubovskiy, also known as Troy. Police superintendent John Price says Dubovskiy came to their attention after sending troubling emails referencing the March 15 mosque attacks in which 50 people were killed.

Price says they searched three of Dubovskiy's properties and found guns, ammunition and violent extremist content.

Police say they located Dubovskiy in a vehicle, then negotiated with him for three hours before approaching the vehicle and finding the man had a mortal stab wound.