The 35-year-old was due to appear in Whakatāne District Court today on charges of murder and wounding with intent to cause grievous bodily harm.
The road was closed while a scene examination was completed and reopened about 2am Sunday.
Warner said on Sunday the victims were known to the alleged offender.
“This is a shocking event and we are still working to understand why this happened.”
He said police were providing the injured person wraparound support.
“Support has been offered to the members of the public who were first on the scene and did everything they could to help.”