Cellular networks in the earthquake-ravaged region of Canterbury are being restored to normal with both generator and mains power, but users are still be urged to stay off their cellphones unless they need to make essential calls.
Cellular networks began to run out of power as batteries went flat after the earthquake led to widespread power cuts across the region following the 7.1 magnitude earthquake at 4.35am.
The batteries at many cellular sites had from three to eight hours life after the power was cut and both Telecom and Vodafone said although the networks did not crash, they immediately encouraged people to stay off their cellphones.
Some cellular calls were affected but both major cellphone companies said the networks generally performed well.
Paul Brislen from Vodafone said 10 generators were being installed today, a further 15 were being shipped in from around the South Island, 12 were shipped from Wellington by sea and 10 were moved from Auckland to Wellington in case they were needed further south.
Power was also being restored to Christchurch area by area, Mr Brislen said.
He said the power network was not badly damaged but power was cut as a precaution.
He said the power should be returned to about 90 percent of Christchurch by the end of the day.
"Hopefully, we won't need the generators but engineers being engineers are saying let's get them there anyway in case there are after aftershocks."
Telecom spokesman Mark Watts said the mobile network had held up well.
"We've got a few sites down, and others are running on battery power," he said.
"But we have 130 to 140 across the region and most are still working fine."
Mr Watts said power outages were potentially a problem and he advised anyone who had an old-style analogue phone in their home to plug it in and use it rather than one powered by electricity.
He said most people had heeded warnings not to use the networks unless it was necessary.
"The loads haven't been excessive and I think people have acted responsibly."
Mr Watts said Telecom and its partners had several hundred staff in the region who were working on and the company was trying to contact them to ensure they were safe.
Robin Kelly, a spokesman for network maintenance company Chorus, said the fixed line network had remained stable.
"We've had a handful of roadside cabinets go down and they have been using alternative power, but the majority of the network is stable and operating as expected."
NZPA