Two powerful earthquakes of magnitudes 6.9 and 7.1 hit off the southern coast of Japan on Thursday, according to the United States Geological Survey (USGS) while the local meteorological agency issued a tsunami warning for coastal areas, expecting waves of up to one metre.

"Tsunamis will strike repeatedly. Please do not enter the sea or approach the coast until the warning is lifted," the Japan Meteorological Agency said on X.

The first quake struck at 4:42pm, at a depth of 33 kilometres, about 29km southeast of Miyazaki on Kyushu.

Less than a minute later, the second quake hit at a depth of 26 metres and was 20km northeast of Miyazaki.

Fortunately, there were no immediate reports of any damage and the situation is being closely monitored by a task force set up by the Japanese government, AFP reported.

Sitting on top of four major tectonic plates along the western edge of the Pacific "Ring of Fire", Japan is one of the world's most tectonically active countries.

The archipelago, home to around 125 million people, experiences around 1,500 jolts every year and accounts for around 18% of the world's earthquakes.

On New Year's Day, at least 260 people died after a massive earthquake hit the peninsula, including 30 "quake-linked" deaths as well as those killed directly in the disaster.

Japan has strict construction regulations intended to ensure buildings can withstand strong earthquakes, and routinely holds emergency drills to prepare for a major jolt.

But the country is haunted by the memory of a massive 9.0-magnitude undersea quake off northeastern Japan in March 2011, which triggered a tsunami that left around 18,500 people dead or missing.