Dr Ben Makalavea from Samoa's main hospital said he needed nurses, doctors, surgeons and blood to treat the increasing number of people with broken bones and cuts.
International Committee of the Red Cross workers were providing food, clothes and water to thousands of homeless now camping in the wooded hills above the coast.
Australian officials said they would send an air force jet carrying 20 tonnes of humanitarian aid, as well as aid officials and medical personnel, to Samoa.
The country's foreign affairs department said three Australians were among the dead.
In American Samoa, officials said about 2,200 people were in seven shelters across the island where at least 30 people had been killed.
"We still have people out on search and rescue missions and we have 27 deaths so far confirmed. We have 2,488 displaced residents in relief shelters," Betty Ahsoon, a spokesperson for the American Samoa homeland security, told AFP news agency.
An aircraft filled with aid flew from Hawaii to the capital, Pago Pago, where debris had been cleared from runways.
New Zealand has provided one million New Zealand dollars ($710,000) in immediate
aid to Samoa, Tonga and the Samoan Red Cross.
Bill English, the acting prime minister, said it was the first "of a long haul for ... New
Zealand ... providing resources.''
"Right now, the focus is on medical and other critical humanitarian aid to ensure survivors are cared for, and basic needs such as shelter, food and water are met," Murray McCully, New Zealand's foreign minister, said.
Officials on the island of Tonga said that seven people had been confirmed killed on the northern island of Niuas, and four critically injured people had been flown out for treatment.
Two of the island's three villages were destroyed.
Aid workers expect an increase in the death toll as they reach more villages and as the bodies of people swept out to sea rise to the surface.