A magnitude 7.1 earthquake has struck near the New Zealand city of Christchurch this morning, causing widespread damage and power cuts that were affecting some mobile services.
The Ministry of Civil Defence and Emergency Management said there were "no reports of deaths, however there have been reports of injuries".
A local state of emergency had been declared in several areas at the time of publication.
Telcos turned to Twitter to check the welfare of customers before reporting on the operating status of their networks.
Vodafone NZ spokesman Paul Brislen tweeted that power was "out to a large number of sites" and that it was working with electricity distributor Orion and Christchurch City Council Civil Defence "to maintain services".
It had rolled mobile sites over to battery back-up supplies which "lasted 3-8 hours typically depending on load" and was working to secure generator supplies.
Voice calls were being prioritised although users were being urged to communicate only in emergencies and via text messages to conserve power supplies and free up the network for emergency services' use.
Telecom NZ said its fixed and mobile services were "standing up well" after the quake.
It reported that a "small number of mobile sites have lost power and some other mobile sites are on battery."
"We're working hard to get back-up power in place across the network as quickly as possible," a spokesman said.
Portable generators were being brought in from "all over New Zealand", the company said.
2degrees Mobile said its network was "operational".
"The majority of our network is unaffected, with only four sites not operating at the moment," chief executive Eric Hertz said.
"Most sites are now running off emergency power and key sites have additional emergency backup generators supplied by petrol.
"Our customers can have the confidence to make calls and send texts as they would normally."
Kordia - which operates telecommunications networks and broadcast facilities in the area - said it was experiencing "no major network impacts".
"Kordia's major broadcast facility for Christchurch (Sugarloaf) has not sustained any damage and is operational. Other sites around the South Island are operational," the company said in a statement.
"Kordia has been working closely with its telco customers to provide assistance."
Hosting firm Where's My Server? was offering free servers to systems administrators and companies affected by the earthquake.
"We've allocated a large server resource pool ready for immediate deployment to those affected by today's earthquake - at no cost," the company said.
"If you have IT infrastructure that was compromised by today's earthquake and need servers up and running fast, we can help.
"All we expect in return is when you experience our service, if you like it - tell your friends."
Banking services cut
The Bank of New Zealand (BNZ) said today that "over half" of its ATM network in the affected region was operational.
"We are working fast to restore the remainder," a spokesman said.
"Over half of our stores are online. However, we will not be opening stores today in line with the Civil Defence recommendation that people stay in their homes."
BNZ was a subsidiary of the National Australia Bank Group.
Geoscience Australia said the earthquake would have been felt in a 1,378 km radius. The damage radius was estimated at 109 km.
It reportedly struck an area 30 km from Christchurch, New Zealand's second-largest city.