At least two people have died in New Zealand after a powerful magnitude-7.8 earthquake struck South Island.
PM John Key said further details were not yet known.
According to US Geological Survey, the tremor hit just after midnight, some 59 miles from Christchurch.
A tsunami arrived about two hours later. Officials warned everyone along the eastern coast to head inland or for higher ground.
According to Weatherwatch.co.nz, a gauge at Kaikoura,112 miles north of Christchurch, measured a wave of 8ft 2ins in the early hours of the morning.
At one point, the ministry of civil defense suggested tsunami waves as tall as 16ft could hit the eastern coast.
By just after 08:00 local time, the warning was scaled back to a “marine and beach threat” with waves of just 3ft along a small stretch of coast, including the Chatham Islands, an archipelago 423 miles south-east of the mainland.
Aerial images show tunnels along the coastal highway close to Kaikoura, a popular tourist destination, covered by a landslide. Other pictures of the devastated area show at least one collapsed home.
New Zealanders are used to earthquakes. The country lies on the notorious Ring of Fire, the line of frequent quakes and volcanic eruptions that circles virtually the entire Pacific rim.
Christchurch is still recovering from the 2011 earthquake that killed 185 people and destroyed the city center.
Japan has issued a tsunami warning after a 7.3 magnitude earthquake struck off the country’s eastern coast.
The quake was felt in the capital Tokyo, media report.
The tsunami warning was issued for the coast of Miyagi Prefecture, which was hit by a devastating earthquake and tsunami in March 2011.
The wave hit the city of Ishinomaki, while the quake was also felt strongly in the capital, Tokyo.
The epicentre of the quake was about 245 km (150 miles) south-east of Kamiashi at a depth of about 36 km, the US Geological Survey said.
Miyagi was hit by a devastating earthquake and tsunami in March 2011.
The US-based Pacific Tsunami Warning Center said there was no threat to the wider Pacific Ocean but that a tsunami could be generated that was destructive for local coastlines.
There have been no immediate reports of deaths or injuries.
Warnings of the tsunami height have varied between 50 cm and 2 m.
Any such height would represent a far lower risk of devastation than the 10-11 metre tsunami that struck in 2011 but that since then the country has clearly become jittery about any shaking of the earth.
At the moment, he says, the damage appears to be on a limited scale, although even a one-metre tsunami could be a significant event.
Japan has issued a tsunami warning after a 7.3 magnitude earthquake struck off the country’s eastern coast
Evacuations have been ordered from some of the affected areas.
A presenter on state broadcaster NHK told viewers: “Remember last year’s quake and tsunami. Call on your neighbors and flee to higher ground now!”
Buildings were reported to have swayed violently in Tokyo.
Prime Minister Yoshihiko Noda cancelled campaigning for the 16 December election to return to his office.
Communications to Miyagi have proven difficult, with the high volume of telephone calls. Trains in the prefecture have been halted and the runway at Sendai airport closed.
English teacher John Heritage, who is in Tagajo in Miyagi Prefecture, said the earthquake was not as powerful as some he had experienced but was worrying as it went on so long.
“We’re now at an official evacuation centre with about 50 other people waiting to hear what to do next,” he said.
Other people reported being alerted to the earthquake prior to its arrival by Japan’s mobile phone-based warning system.
One tweeted that he was given 10 seconds and was able to slow his car before the shaking struck.
The USGS reported three aftershocks in the same area, of 6.2, 5.5 and 4.7 magnitudes.
The 9.0 magnitude quake that struck on March 11th, 2011, caused a devastating tsunami and left more than 15,000 people dead, with more than 3,200 missing.
That quake triggered a meltdown of fuel rods at the Fukushima nuclear plant, causing radiation leaks and mass evacuations.
The plant’s operator, Tokyo Electric Power, told Agence France-Presse there were no reports of problems there this time, although workers have moved to higher ground.