The country's three emergency services say Telecom has assured them it will thoroughly investigate what went wrong with 111 calls in Te Kuiti.
The system was out of action for up to three hours on Tuesday after a Telecom technician failed to alert superiors to a fault.
The problem was discovered when it took nearly 10 minutes for a 111 call to be logged after a fatal crash on the road between Te Kuiti and Benneydale.
Telecom spokesperson Mark Watts told Morning Report a fault in the district's local exchange masked the usual alarm associated with a 111 fault.
"That was then compounded later in the day," he said, "by I guess what I'll call a failure in the chain of human communication."
Crash was only incident affected
In a joint statement the police, fire and ambulance communication centres say they've expressed their concern to Telecom.
They say company is well aware of the critical nature of 111 and is taking the failure very seriously.
The three services say it appears the car crash was the only incident affected by the failure.
Otorohanga mayor Dale Williams says the failure was appalling and investment is needed to ensure essential services are working properly for rural communities.
Mr Williams says there have been problems before, caused by contractors cutting through lines, and Telecom has done nothing more than apologise.
"We would be encouraging Telecom to try harder, work harder," he said.