An internal Fire Service bulletin obtained by Radio New Zealand News says that the service was not consulted by Spark over the company's decision to shut down its paging network.
Spark announced last week it had decided to decommission the network that the emergency services rely on.
The Fire Service bulletin was sent out to all personnel from the acting deputy national commander, Brendan Nally, on 29 July, two days before Spark made the official announcement.
In the bulletin Mr Nally said: "The Fire Service was not consulted on this important move, or its timing, and it will take up the matter with Spark."
He said the Fire Service would now look at alternatives as a priority and the strategic leadership team would also urgently discuss the matter.
He moved to assure firefighters that their ability to respond to callouts was critical, and it would not be compromised.
"Dealing with this decision and its implications is a high priority for the organisation."
In response to Radio New Zealand queries Spark said it had talked to many of its customers before the announcement was made and that included the Fire Service.
It said it had discussed paging alternatives and the limited lifespan of the network. Spark added that there were a number of alternative mobile-based messaging solutions.
The Fire Service said it was surprised by the move but this was largely due to different interpretations of the contract.
Mr Nally said the service had begun discussions with Spark about its options "and (we) have every confidence we can find a solution that meets our needs for reliability and coverage."