Police say the public needs to have full trust and confidence in the emergency 111 system and its failure in Auckland is not good enough.
Telecom did not notify police that there was a fault with the 111 system early on Friday and says it does not know why police were not told.
The Government is calling in independent experts to take part in Telecom's inquiry into the failure and the company could be financially penalised for the disruption.
Police say they were not aware there was a problem until an officer tried to make a 111 call and then radioed through to advise that the system was not working.
The intermittent failure at the Telecom's Papatoetoe exchange started just before 4am and police say that during that time 33 calls to 111 system were not connected.
Of these, 15 were genuine requests for emergency services. Service was restored about 8.30am.
Superintendent Andy McGregor says the public needs to have full trust and confidence in the 111 system and the failure on Friday is "not good enough".
Mr McGregor says police have been let down by the fact Telecom did not tell them about the system failure and the company has accepted it should have done so.
Police have not been notified of any serious consequences as a result of the failure.
The ambulance service says it is worried about any failure that prevents the public being able to contact emergency services.
Alan Goudge, of the ambulance emergency communication centre, says two of the calls on Friday required an ambulance response.
Mr Goudge says there would have been a very slight delay in the response to these calls - but in their business, minutes count.
Telecom can't explain why police not told
Telecom says it does not know why police were not alerted immediately to the fault.
Media relations manager Mark Watts told Checkpoint on Friday the company's formal procedure and interactions with police will be the subject of a review.
However, Mr Watts says none of the 33 callers were left hanging, as their calls triggered alarms alerting Telecom which called them back within minutes.
Police also contacted these customers to make sure everything was all right.
Telecom says Friday's fault was caused by a software failure and is not related to ongoing problems with its XT mobile network which has disrupted thousands of customers since December.
Telecom has begun an inquiry into the failure of the emergency system.
Communications Minister Steven Joyce says the Government will have independent experts involved in the review.
Mr Joyce told Nine to Noon the inquiry will look at why the fault occurred, why calls were not automatically diverted away from the fault and Telecom's response.
The minister says Telecom could face financial penalties for the disruption and such a large failure of the 111 service is thought to have been unprecedented.