Phone connections into Te Anau, Southland, have been knocked out as floods force helicopter evacuations of more than 100 trampers in the area.
Civil defence and police have been spurred into action as scientists predict the Oreti River, which passes just west of Invercargill, will swell to the maximum level its flood protections can cope with tonight.
Rivers have surged as a result of heavy rains, putting six state highways at risk from flooding, and drowning stretches of farmland, causing “extensive damage”.
More than 700mm of rain during the past three days has flooded the Milford Track, north of Te Anau.
Telecom said phone communications to 2000 people in Te Anau had been lost after the Whitestone River, south of the town, broke its banks and disrupted a main network connection.
The Department of Conservations said email and land line connections into Te Anau had been lost this afternoon.
Telecom spokesman Brett Jackson said one of the main telephone network connections into the area had been put at risk by the floods and the company was trying to confirm details.
Rescue for trampers underway
Meanwhile, a helicopter rescue is underway for 120 trampers on the Milford Track who spent the past two nights inside huts.