Before considering any technology problems, it's worth remembering that the pre-Christmas 'quake resulted in no fatalities and only 19 hospital admissions:
http://www.bbc.co.uk/news/world-asia-16312041
Communications in the Christchurch area were certainly disrupted, as this quote shows:
"People were being urged to use text instead of voice calls on mobile phones to check on friends and relatives, as the phone lines still in operation were increasingly jammed"
http://www.the9billio...kes-hit-christchurch/
although this site
http://online.wsj.com...-20111222-715365.html
says
"Telecom spokesperson Katherine Murphy said that the network has held up and, after initial cell phone overloading, everything seems to be back up and running and there is no obvious damage to their infrastructure"
As the previous poster suggests, the New Zealand High Commission might be able to assist you:
http://www.nzembassy....commission/contact-us
Chris