The Government sent the Orion to help search for survivors and assess damage after this morning's magnitude 8 earthquake and subsequent tsunami.
Up to 34 are dead in Samaoa and American Samoa, with the toll expected to rise to beyond 100.
Foreign Affairs Minister Murray McCully's office has received reports of people being washed out to sea following the tsunami.
Mr McCully said New Zealand's diplomatic missions throughout the Pacific were in contact with local authorities.
New Zealanders in Samoa should follow the instructions of local authorities, stay away from the sea and listen to the local radio, he said.
Anyone concerned about family they could not contact should call the Ministry of Foreign Affairs and Trade, Mr McCully said.
Concerns about non-relatives should be directed to the Samoan High Commission.
Tonga was hit by 4m waves which have caused damage.
People had moved to higher ground and no casualties had been reported despite the "significant" waves, a spokesman for Mr McCully told NZPA.
Samoa was hit with 6-8m waves on the south coast earlier today.
Seventy-six New Zealanders were registered with the Ministry of Foreign Affairs and Trade as being in Samoa but there were likely to be many more school holiday travellers, the spokesman said.
There were "bigger than usual" waves in the Cook Islands, with swells up to 1m being reported in Rarotonga.
In Suva, Fiji there were reports of waves hitting around 10am local time but no damage was reported.
Tokelau, Niue, Vanuatu, Kiribati, New Caledonia and the Solomon Islands had not reported high waves.
Deputy Prime Minister Bill English was returning to Wellington from his home in Dipton to deal with the situation. He is to update media this afternoon at a conference with Mr McCully and Civil Defence and Emergency Management director of John Hamilton.
