An earthquake on New Zealand's Cook Strait did not damage Telecom NZ and Vodafone networks, but precipitated a large number calls that congested both networks.
Both telcos closed major offices and stores in Wellington and sent staff home.
The 6.8 earthquake hit near Wellington on New Zealand's South Island, according to news reports.
"Telecom advises that no significant damage appears to have been sustained to its networks in the Lower North Island / Upper South Island as a result of this afternoon's Cook Strait earthquakes," the telco said in a statement this afternoon. "For a period of time after the major earthquake hit just after 2.30pm, our networks experienced severe congestion as a result of many people trying to make calls to loved ones."
Telecom said 111 services are still operated, but traffic normally routed through a call centre in Wellington has been diverted to Christchurch.
The Vodafone network did not sustain "any significant damage," but two sites in central Wellington momentarily lost power, Vodafone NZ said. Like Telecom, a mass number of calls created congestion on the network, it said.
Scheduled upgrades at two sites--Wingate and Gracefield in Lower Hutt--were stopped due to health and safety concerns, rendering the sites not operational, Vodafone said.
"One roadside cabinet is currently without power, which will affect fixed broadband access for Vodafone customers in Paraparaumu. The cabinet will come back online once power is restored."
Telecom and Vodafone recommended that customers use SMS rather than make phone calls, unless urgent, to allow emergency calls to be made.
Follow Adam Bender on Twitter: @WatchAdam