Tsunami waves are now being reported along the entire Pacific coast of Japan and Russia, after the world’s biggest earthquake in 14 years sparked warnings for millions in the northern hemisphere.

Wave heights have reached up to 60cm in areas such as Kuji Port and Hamanaka town, rising from 20cm earlier in the morning. Authorities warn the waves could swell to as high as three metres.

So far, the worst-hit nation has been Russia.

Images from the Pacific town of Severo-Kurilsk show damage caused by waves that reportedly exceeded three metres in height. One wave reached as high as five metres, according to local authorities.

Another video showed buildings in the town submerged in seawater.

Authorities said the population of around 2,000 people was evacuated safely after several people were injured by the quake

“The walls were shaking,” a Kamchatka resident told Russian state media.

“It’s good that we packed a suitcase, there was one with water and clothes near the door. We quickly grabbed it and ran out... It was very scary,” she said.

Tsunami waves appear to be reaching Hawaii as well, with water levels rising suddenly around Kahului, Nawiliwili, Honolulu and Pearl Harbor.

Evacuation shelters have been set up as the island state braces for what could be a devastating night.

Russia, along with the entire west coast of America and the Pacific islands, have also been issued tsunami warnings.

The quake reached a magnitude of 8.8 and struck off east-southeast of Kamchatska off the coast of Russia, about 9.24pm (AEST).

It is the largest earthquake to hit since 2011, when a 9.1 megaquake hit northeast Japan and left 19,747 people either dead or missing — and it is the strongest in the region since 1952.

The Pacific Tsunami Warning Center has added Australia to its advisory, saying waves of 0.3 to 1m are possible along the east coast.

Meanhwhile, the National Tsunami Warning Center in the US has issued a tsunami advisory for the entire West Coast — all the way up into Canada and Alaska.

The advisory stretches from California’s border with Mexico up through Oregon and Washington and into British Columbia in Canada before continuing to South Alaska and the Alaska Peninsula.

Donald Trump urged Americans to “stay strong and stay safe”.

“Due to a massive earthquake that occurred in the Pacific Ocean, a Tsunami Warning is in effect for those living in Hawaii. A Tsunami Watch is in effect for Alaska and the Pacific Coast of the United States. Japan is also in the way. Please visit tsunami.gov/ for the latest information. STAY STRONG AND STAY SAFE!” he wrote.

Hawaii’s coast guard has advised all vessels to leave port on all islands.

The first waves in Hawaii were expected around 7pm local time, which is 3pm (AEST).

Japan has ordered immediate evacuations for more than 900,000 people, as tsunami waves begin to hits the nation’s coast.

Workers at the stricken Fukushima nuclear plant in northeast Japan have been evacuated.

“We have evacuated all workers and employees” at the Fukushima Daiichi plant — which went into meltdown after being hit by a tsunami in 2011 — a spokeswoman for plant operator TEPCO told AFP, adding that “no abnormality” had been observed at the site.

The first tsunami was observed in northern Japan, measuring around 30 centimetres, broadcaster NHK reported.

The wave hit the main northern island of Hokkaido, with NHK warning that subsequent waves could be much higher.

Japan’s weather agency said earlier that waves of up to three metres were expected all the way down the northern and eastern coasts of Japan, as far as Wakayama south of Osaka.

Tsunami warnings are in effect for a major stretch of Japan’s eastern Pacific coast, from Hokkaido’s eastern Pacific coast down to Wakayama Prefecture.

“A tsunami advisory has been issued as of 08:37 on July 30,” the Japan Meteorological Agency said on X, warning that “tsunamis will strike repeatedly. Do not enter the sea or approach the coast until the warning is lifted.”

Tsunamis of up to one metre were expected to hit between 10am and 11.30am, public broadcaster NHK said, calling for residents to stay away from coasts and riversides.

A tsunami has hit Russia’s far east coast, flooding a port town home to around 2,000 people, Russia’s emergencies ministry said.

“The tsunami flooded parts of the port town of Severo-Kurilsk ... The population has been evacuated,” the ministry said in a statement.

A video posted on Russian social media appeared to show buildings in the town submerged in sea water.

New Zealand issues tsunami alert New Zealand authorities have warned people in coastal areas to stay away from beaches and shore areas.

The U.S. Geological Survey (USGS) said the earthquake was shallow at a depth of 19.3km, centred about 125km east-southeast of Petropavlovsk-Kamchatsky, a city of 165,000.

The USGC has recorded six earthquakes in total off the coast of Russia, with initial readings of magnitude 6.9, 6.3, 5.4, 5.7 and 5.6.

A tsunami advisory alert has been issued for the island of Guam, a US territory in Micronesia, according to the USGS.

In Hawaii, residents have been sent “extreme” emergency alert texts telling them to move to high ground and keep away from the coast.

Officials in Hawaii have ordered evacuations of large parts of Oahu, including coastal areas of Honolulu.

The Oahu Emergency Management department says “destructive tsunami waves” were expected to hit the coast.

A map of evacuation zones shows the entire coast of Oahu was at “prepare to evacuate” status.

New Zealand authorities have warned people in coastal areas to stay away from beaches and shore areas.

There is no need to evacuate unless ordered to be local authorities, the National Emergency Management Agency said.

Several people were injured in Russia’s far east when a powerful earthquake struck, state media reported.

An 8.8 magnitude earthquake was the region’s strongest since 1952, with aftershocks of up to 7.5 magnitude possible, the regional seismic monitoring service said, per Agency France-Presse.

Kamchatka’s geophysical service said: “The strongest earthquake since 1952 has just occurred in the Kamchatka seismic zone … Given the scale of the event, strong aftershocks with a magnitude of up to 7.5 should be expected.”