Foreign Minister Murray McCully had been in touch with the Solomon Islands Government and "made it clear we're here to help if we can".
Japan's Meteorological Agency reported a 40-centimetre tsunami hitting Hachijo Island about 290 kilometres south of Tokyo, while 20-centimetre waves reached the main islands of Kyushu and Shikoku and smaller waves were recorded on Honshu.
The Pacific Tsunami Warning Centre cancelled its regional alert for Pacific-island nations at 1450 AEDT, about two and a half hours after the powerful quake struck near the Santa Cruz Islands in the Solomons.
Australian and US monitors said a tsunami wave measuring 91 centimetres washed into the town of Lata, on the main Santa Cruz island of Ndende.
The United Nations Office for the Coordination of Humanitarian Affairs said the wave appeared to have travelled 500 metres inland, inundating Lata's airstrip as well as surrounding villages, flattening many traditional houses.
"We can report five dead and three injured. One of the dead was a male child, three were elderly women and one an elderly man," Chris Rogers, a nurse at Lata Hospital, told AFP.
Solomons Prime Minister Gordon Darcy Lilo's office said four villages on the Santa Cruz Islands had been hit by the tsunami.
"Latest reports suggest that between 60 to 70 homes have been damaged by waves crashing into at least four villages on Santa Cruz Islands,'' Lilo's spokesman George Herming told AFP.
"At this stage, authorities are still trying to establish the exact number and extent of damage. Communication to (the) Santa Cruz Islands is difficult due to the remoteness of the islands."
Solomon Islands Red Cross secretary general Joanne Zoleveke said she had been told at least three villages were hit, with houses washed away.
"In the Solomon Islands when we talk about villages there can be anything from 10 to 30 houses,'' she said.
With Lata's airstrip out of commission, officials were hoping to fly over the area early on Thursday to assess the damage better.
The US Geological Survey said the quake struck the Santa Cruz Islands, which have been rocked by a series of strong tremors over the past week, at a depth of 28.7 kilometres.
Dozens of aftershocks continued through the day, including one at 6.6-magnitude.
"Sea level readings indicate a tsunami was generated," the Hawaii-based Pacific warning centre said after the 8.0 quake, before lifting its tsunami alert for several island nations.
Lata Hospital director of nursing Augustine Bilve said some patients were evacuated to higher ground to prepare for any injured from the villages along the coast.
Settlements did not appear to be seriously damaged in the quake, he said, but added: "We were told that after the shaking, waves came to the villages."
In 2007 a tsunami following an 8.0-magnitude earthquake killed at least 52 people in the Solomons and left thousands homeless. The quake lifted an entire island and pushed out its shoreline by dozens of metres.
The Solomons are part of the Ring of Fire, a zone of tectonic activity around the Pacific that is subject to earthquakes and volcanic eruptions.
In December 2004, a 9.3-magnitude quake off Indonesia triggered a catastrophic tsunami that killed 226,000 people around the Indian Ocean.
VILLAGERS RUN FOR THEIR LIVES
Homeless villagers sought shelter on high ground as rescue efforts began in the tsunami-struck Solomon Islands.
World Vision said at least 100 homes had been destroyed and Government officials confirmed five people had died.
"I am currently walking through one community [in Lata], and I'm knee-deep in water," said Jeremiah Tabua, World Vision's emergency response co-ordinator in the Solomons. "I can see a number of houses that have been swept away by the surge."
The tsunami was triggered by a magnitude 8 earthquake that also caused panic in other Pacific countries and led to Civil Defence placing New Zealand and other nations on tsunami watch, a step below a full alert.
The hardest-hit areas in the Solomon Islands were four villages in Temotu province in the Santa Cruz group where waves of up to 1m swept ashore and reportedly damaged dozens of homes and properties.
Jared Berends, 35, a New Zealander with World Vision in the Solomons, told the Herald panicked villagers ran for their lives when they saw the water coming, which they described as a "tidal surge".
A World Vision staff member was speaking to her sister on the phone when the tsunami hit.
"She ran down the two-storey office and as she did so could see the water starting to come up ...
"Our staff were literally talking to her as she said, 'tsunami', put the phone down and ran out the door," Mr Berends said.
Earthquakes had shaken Lata, the capital of Temotu province and the largest town on the island, all week so there was some awareness of the possibility of a tsunami.
"Most of the communities had been feeling them so there was high alert and some had already gone to higher ground by that point as well - but there was still a mad rush to get to higher ground."
Communication with the affected areas was difficult. "We've had reports that many homes there have been completely destroyed."
There were unconfirmed reports of children being swept away.
Mr Berends said people on Santa Cruz were fearful of the aftershocks but believed the immediate tsunami threat had passed.
In New Zealand, the Ministry of Civil Defence and Emergency Management warned of the threat to beaches as well as marine areas in many coastal areas.
It warned people to stay out of the water, off beaches and to avoid sightseeing.
The ministry said unusually strong currents and unpredictable water flows could be expected near the shore, which could be a threat to beach, harbour, estuary and small-boat activities.
Kirsty Taylor-Doig of the New Zealand Defence Force confirmed eight staff in the Solomon Islands were unharmed.
In April 2007, more than 50 people were killed and thousands lost their homes when a magnitude 8.1 quake hit the western Solomon Islands, sending waves crashing into coastal villages.
The Solomons comprise more than 200 islands and have a population of about 552,000 people.
TSUNAMI EXPERT FEARED THE WORST
When the magnitude 8 earthquake struck yesterday scientists feared the worst.
It was initially thought the depth was 5km but that was later confirmed to be 33km deep - and that saved the Solomon Islands from a far more destructive tsunami, Professor James Goff said.
Professor Goff, director of the Tsunami and Natural Hazards Research Group at the University of New South Wales, said the initial reports made him think, "Oh no, here we go again, this will be a bad one".
Where the earthquake hit was part of the Solomon Islands that was particularly active - part of the boundary between the Australian and Pacific plates - and has seen a swarm of earthquakes recently.
"In geological terms, this is hot on the heels of the 2007 event that occurred in the Western Province and killed 52 people - an area of different plate boundaries and different activity, but in reality we know very little about the long-term earthquake and tsunami activity of the entire Solomon Islands region and so cannot say with any confidence whether this type of event we have seen today is out of the ordinary or how often we might expect it to happen in the future."
He said to improve understanding of such earthquakes more work needed to be done and this would benefit countries around the Pacific.
Professor Goff said it would take time to assess how significant the tsunami had been and warned some of the available data could be misleading.
"We hear that a tsunami of around 90cm was recorded at Lata. We need to remember that this is the amplitude of the wave - the height from peak to trough, and also that this would have been recorded at a tide gauge, not on the land. Tsunamis on land can run up considerably higher than their offshore height, hence we hear that some coastal communities have been destroyed."
PUBLIC PRAISED FOR TSUNAMI RESPONSE
The public responded effectively to a tsunami advisory yesterday after an magnitude-8 earthquake struck near the Solomon Islands, Civil Defence says.
Six people have died and three are understood to be missing as a result of the quake that struck 340km east of Kira Kira in the Solomons, prompting tsunami alerts.
Last night a tsunami potential marine and beach advisory for New Zealand was cancelled.
The Ministry of Civil Defence and Emergency Management (MCDEM) said today it was pleased with the public's response to its warnings, saying the public responded well and media communicated messages to communities swiftly and accurately.
"The public was very co-operative, although many were not aware there was a warning due to the public holiday," it said.
"Yesterday it wasn't an issue of clear the beaches rather than not being in restricted water," said a spokesman.
No signs of unusual water behaviour around New Zealand were recorded overnight.
However, a minor threat still remains on the West Coast from Taranaki to Milford Sound and boaties and swimmers should watch out for strong currents and surges
"Advice from GeoNet Tsunami Expert Panel is that there may be unusual water conditions e.g. local tidal surges and strong currents, especially during the early hours of Thursday 7 February. People should exercise caution and discretion before entering the water or going out in small boats," MCDEM said.
FORESHOCKS INDICATED BIGGER QUAKE TO COME
The magnitude 8 quake was preceded by several days of foreshocks, seven of them greater than magnitude 6.
GNS Science duty seismologist Caroline Holden has been keeping an eye on the region since the first quake in the sequence, a magnitude 6 tremor on Janurary 31.
She said it was not common to have a large quake preceded by so many decent-sized jolts.
"I don't think it is usual, I think it is special that we've had this sequence followed by a magnitude 8."
Since the largest quake in the sequence there has more than 70 aftershocks larger than magnitude 4, with four shocks stronger than magnitude 6.
Ms Holden said another large jolt could not be ruled out.
"It is not unlikely we could get another one, but the risk will go down as time goes by. The region is capable of producing really large earthquakes."
She expected the sequence to continue "for some time".
- NZ Herald, AFP, APNZ, AP
