Twitter began to light up with word that  another major earthquake struck Christchurch at around 1pm this afternoon, February 22nd.

You can follow live updates on Twitter using the #eqnz tag.

The Civil Defence has regular updates here.

Government helpline: 0800 779997

All phones are said to be out and the quake is said to have measured 6.3.

Using Twitter as a means of communication Telecom has said, "We're investigating situation in Christchurch, will update when we can."

Likewise with Vodafone: "We're checking the status of network in CHCH, will update when we can."

Vodafone has told us that it will put all the info it has on Twitter and send out a statement with all info once it's been collated.

Christchurch police have said that the Cathedral has taken a big hit.

2degrees says it's free helpdesk number is 0800 022022 or 200 from a 2degrees mobile.

TelstraClearNZ Special EQNZ numbers:

Residential customers can call 0508 24 24 11 (CH CH 11)

Business customers can call 0508 24 24 12 (CH CH 12)

Vodafone and Telecom have said to not overload phone lines with non-emergency calls, "stick to TXT and short calls if you can".

We've received the following statement from Vodafone: "We are currently prioritising the safety of our people and our stores. Our core network is functioning as per normal, although we have sustained damage to approx eight sites and have a large number running on battery. There is heavy congestion on the network and we encourage people to text rather than call in order not to overload."

Orcon has made all calls in and out of the South Island free for the next 48 hours and said its network is unaffected.

AM frequencies are out so Newstalk ZB is now broadcasting on 91.3FM, 97.7FM and 106.5FM in Christchurch.

Alcatel-Lucent's Christchurch office has suffered extensive damage, with buildings either side having collapsed.

Telecom has also reported "heavy damage" to its Christchurch base and said that eight cellphone towers are down throughout the city.

Air New Zealand flights in and out of Christchurch up to 7.00pm are cancelled.

Mighty Ape has been advised by Courier Post to expect delays for shipments headed to the South Island.

Police have said the 111 service is still working despite some people experiencing difficulties.

Telecom says that 111 services are stable and the Christchurch 111 call centre has been successfully diverted to Wellington.

We're hearing reports that scammers pretending to be PC Doctors are already calling up houses to offer their services.

Google has launched a Person Finder. Take a look here.

TelstraClear's call centre has been evacuated and all staff have been sent home.

TVNZ has posted the following raw footage on YouTube: