The Australian government has doubled the number of urban search and rescue specialists being deployed to New Zealand to help with the Christchurch earthquake disaster.

Attorney-General Robert McClelland said overnight "A total of 148 Australian Urban Search and Rescue specialists are now being deployed to Christchurch at the request of the New Zealand Government."

"Seventy-four specialists are being deployed from NSW and now an additional 74 Queensland Urban Search and Rescue experts will be sent tomorrow morning.

"The first 40 specialists are departing from RAAF Richmond airbase tonight on board an Australian Defence Force C130, along with rescue equipment and supplies.

"A further 34 specialists from NSW is also scheduled to depart overnight from RAAF Richmond base, while the 74 Queensland specialists will leave from Amberley RAAF Base later in the morning on board a C17 Globemaster.

The rescue teams Australia is deploying are experts at recovering people who are trapped or affected by structural collapse and consist of highly trained emergency services workers, doctors, engineers and search dogs.

"They have expert search, rescue, medical, engineering and support capabilities," Mr McClelland said.

Australia continues to remain in regular contact with New Zealand to offer any assistance.

The Aussie government is also deploying two Emergency Management Australia Liaison Officers to New Zealand to ensure this assistance is provided as quickly as possible.

Mr McClelland said the government is also preparing to offer more assistance, including specialist medical teams.

"New Zealand was one of the first countries to offer assistance to Australia during the floods crisis and we will continue to do what we can to help our friends across the Tasman through this catastrophe," he said.

"The thoughts of all Australians are with New Zealanders as they cope with this tragic situation tonight.

"The Australian government will continue to get whatever assistance is required to New Zealand."