A magnitude 7.3 earthquake struck off Japan's north-eastern coast today, shaking buildings hundreds of miles away in Tokyo and triggering a small tsunami.

There were no immediate reports of significant damage or injuries.

The quake struck at 11.45am local time and was centred about 90 miles off the north-eastern coast - about 270 miles north-east of Tokyo - at a depth of about five miles, Japan's meteorological agency said.

A 24-inch tsunami reached the coastal town of Ofunato, in Iwate prefecture, with other towns reporting smaller waves reaching shore about 30 minutes after the quake.

"We have confirmed that small tsunami have come up on the shores, but we have no reports of damage at this point," said Shinobu Nagano, an emergency and disaster response official in Iwate. "We are still trying to determine the impact of the quake."

Some train lines in the area were temporarily stopped after the quake, but they were restarted shortly after noon. Tohoku Electric Power said there was no damage at its nuclear power facility in the region.

The Pacific Tsunami Warning Centre in Hawaii said a Pacific-wide tsunami was not expected.

There was a 6.3 magnitude aftershock shortly after the main quake, the meteorological agency said.

In Tokyo, office buildings swayed and creaked for about 30 seconds during the quake.

Japan lies on the Ring of Fire - an arc of earthquake and volcanic zones that stretches around the Pacific Rim and where about 90% of the world's quakes occur.

In 1933, about 3,000 people were killed around Ofunato by an earthquake and tsunami that had a maximum wave height of 94ft, according to the USGS. In 1896, a magnitude 8.5 earthquake generated a tsunami that killed 27,000 people in the area.