Aid has begun arriving in Samoa in what will be an ongoing effort as the scale of devastation from yesterday's earthquake and tsunami becomes clear, Acting Prime Minister Bill English said today.

A New Zealand air force Hercules had arrived last night with medical supplies, medical teams and temporary morgue facilities to help the overwhelmed hospital in Apia.

The New Zealand Hercules and one from Australia would begin a ferrying operation taking in urgently needed basic supplies such as food, shelter and water.

A team of police officers with expertise in body identification would also be sent to Samoa.

The navy multi-role ship Canterbury was being taken out of maintenance and would be ready to sail in two days.

The ship would take four days to arrive and would be able to carry substantial assistance, Mr English said.

This would include heavy machinery, building materials a large water purification plants, more morgue facilities, engineers and communications support.

"It has significant capacity," Mr English said.

An Australian C17 air force plane would be arriving in New Zealand to ferry up to three helicopters to Samoa.

Mr English said an Orion would remain in the area in the hope of spotting survivors at sea. The photographs it had sent back showed the area "had just been devastated".

The air force had a Boeing 757 on standby if it was needed, but Air New Zealand had done a good job in raising capacity to get New Zealanders home.

Mr English would be talking to Samoa's prime minister in the next few hours to see what specific help was required and it was likely a member of the New Zealand Cabinet would be travelling to the island.

"We want to make sure the Samoa government feels totally supported by the New Zealand Government and the Samoan community here can see the Government has real concern."

An initial decision on financial aid to assist NGOs in the area would be made shortly.

New Zealand's commitment to rebuild Samoa would be a long term one. At moment the priority was to contain and stabilise the emergency impact.

The New Zealand Government was committed to helping Samoa rebuild, "we are in for the long haul," Mr English said.