Almost 2000 residents of Te Anau are without landline, mobile phone and internet services, after snow damaged the system on Saturday night.
Snow has cut the power supply to the area's microwave radio site at White Hill and bad weather meant back-up generators could not be manned all night.
Chorus, the company responsible for the area's network, says it is sending a helicopter to its damaged microwave radio site at first light on Sunday.
Emergency service calls are being taken manually until the problem is resolved.
