Police will not be able to speak to the man they say went on a rampage through Christchurch city on Thursday until Saturday morning.
He was shot in the shoulder and wrist at close range by police Thursday after allegedly repeatedly stabbing a Christchurch City Council worker and a female delivery driver.
The Somalian immigrant, 27, who the police say carried out the attacks remains in an induced coma.
Detective Inspector Greg Williams says the police will be seeking a psychiatric report when the man has recovered from his injuries.
Meanwhile, the Christchurch City Council worker who was stabbed has emerged from his induced coma.
He was hospitalised along with a delivery woman, who was stabbed after having her truck hijacked by the alleged attacker.
Police say they are mystified as to the motive for the attacks.
Police have spoken to the man's family who say they are shocked by the incident and have expressed their condolences to the victims.
Police will be seeking a psychiatric report when the attacker is well enough to be interviewed.