The Government has set aside $2.4 million for trauma counselling for Christchurch earthquake victims, Paula Bennett says.

The state of emergency in Christchurch has been extended a further seven days following an aftershock of 5.1 on the Richter scale this morning.

An open source online map has been set up to help Cantabrians find help nearest to them.

Stricken homeowners and workers will start receiving compensation and emergency payouts within days as Christchurch's earthquake bill threatens to exceed $2bn.

Rebuilding up to 100,000 damaged and destroyed homes in quake-hit Canterbury could take years, a building executive says.

The Christchurch earthquake is expected to provide a much-needed lifeline for NZ's beleaguered construction sector.

There have been nearly 5,000 insurance claims made already as a result of the Christchurch earthquake, says the Earthquake Commission. Here's how to make a claim.

Christchurch was "inevitably going to be brought to its knees" by an earthquake because of the nature of the ground it stands on, a scientist says.

"It's essentially a ghost town. You can see utter devastation," said Prime Minister John Key.

The cost of damage from today's devastating quake could be as much as $2 billion, Earthquake Commission chief executive Ian Simpson says.