Thousands of Telecom customers in the South Island are having problems with cellphone reception.
Telecom says it is aware of the problem, but a spokesman was unsure when the fault would be fixed.
The widespread problem manifests itself in strange ways, with callers sounding as if they are under water or as if an alien life form is attempting to make contact.
Spokesman Richard Irvine said the fault had been traced to a failing element in the network serving a large portion of the South Island.
He was unsure what specific component was faulty, but said it was a piece of infrastructure such as a server.
The problem had developed over the past week and was probably exacerbated by increased network traffic as people called and texted family and friends over the New Year holiday.
"We want to apologise to people for the problems that they're having," Irvine said.
"It's definitely not the usual quality of service we want to deliver."
The problem was particularly affecting customers in the lower South Island, he said.
On the Timaru Herald Facebook page, people reported problems making calls from the West Coast, Nelson and Palmerston North.
Irvine said Telecom would try to fix the fault as soon as possible.
However, he was unsure how long it could take. In the meantime, he advised customers to contact Telecom and log any faults they experienced.
"That will give us data to investigate and will make sure that their individual fault is related to this issue," he said.
Customers can report faults by calling 120 from their cellphone or going to the Telecom network faults site online.
- The Press
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