Telecom has released the details of its compensation deal for XT customers, following the failure of the service on Monday.
The system was down from south of Taupo for about 11 hours, with Telecom blaming a technical fault at its Christchurch control centre.
Telecom chief executive Paul Reynolds says as compensation, the company will credit customer accounts with all mobile calls made a week ago, on Monday, 7 December.
He says in addition, all calls by XT customers to Telecom landlines and mobiles this weekend will be free.
The offer applies from midnight on Friday to midnight on Sunday, with the credits applied to accounts automatically.
The Telecommunication Users Association says the fault suggests the lack of a back-up system that would normally be used to reroute the service when the network fails.