The Japan Meteorological Agency (JMA) has issued a tsunami warning following an earlier volcanic eruption in Tonga.
The weather agency on Saturday midnight warned of the tsunami on the country's Pacific coast and urged residents to evacuate from seaside areas, Xinhua news agency reported.
The tsunami was triggered following the massive underwater volcanic eruption in the South Pacific island country of Tonga on Saturday.
So far, part of the Amami Island saw a tsunami about 1.2-metre high, while many eastern Pacific coastal areas were hit by a tsunami of 0.4 to 0.6 metre high, according to the JMA.
The agency has predicted that a 3-metre tsunami may hit some of Japan's southwestern islands including Amami Island, while other Pacific coastal areas will likely be hit by a tsunami around 1-metre high.
After the agency issued the tsunami warning and advisories, the government set up a liaison office at the Prime Minister's Office to gather information.