Police have apologised to a woman for acting too slowly after she called emergency services twice for help, before being stabbed by her mentally ill son.
An inquiry by the Independent Police Conduct Authority (IPCA) found the police should have responded to the woman's first call for help.
The two 111 calls were made by a woman in Omapere, Northland on 26 October 2015.
The woman's mentally ill son stabbed her before police arrived. She was taken to hospital by helicopter and survived the attack.
The woman initially called about 6am and reported that her son - who had a history of serious mental health problems and was known to police - was behaving erratically and had pushed her.
Police put the event 'on hold' until a pre-existing Mental Health Crisis Team appointment took place at 10am, but the woman rang a second time at 10.43am, saying the Crisis Team would not take her son away because they did not consider him to be sick enough.
The woman told police she feared for her safety and did not want her son to stay in the house.
Two officers who were in Omapere on an unrelated matter were contacted, but before they could reach the woman, police received a third 111 call at 11.15am, reporting that the woman had been stabbed by her son.
The IPCA found that police should have been sent to the scene after the first 111 call, due to the woman's concerns for her and her family's safety.
"The NorthComms dispatcher should have passed on all of the relevant information from this 111 call to the field supervisor before they decided it was unnecessary to dispatch the on-call officer to attend the incident. Additionally, police should not have closed the event without advising her of their decision not to attend.
"Police underestimated the woman's concerns and did not respond to the first or second 111 calls with enough urgency."
Superintendent Dave Trappitt said police underestimated the situation and should have responded with more urgency.
He said a major error was also made when officers did not call back after the woman's first emergency call.
"That call back to the victim might have elicited further information that could have prompted us to attend sooner. So in that regard, we missed an opportunity to intervene and that opportunity might have had a different outcome for the victim."
Mr Trappitt said a full internal review had taken place, and officers now received more training over mental health.