A Japanese volcano has erupted shooting ash nearly two kilometres into the night sky along with fountains of lava.

The incident took place about 50 kilometres from a nuclear plant, but there were no immediate reports of damage and operations at the power station were not affected.

Following what they termed an "explosive eruption", Japan's Meteorological Agency raised the warning level on the peak to three, meaning that people should not approach the mountain.

"It appears that stones have been thrown about two kilometres from the crater, but this area is quite far from any communities," Kazuhiro Ishihara, an emeritus professor at Kyoto University, told NHK national television.

Television footage showed red streams of lava bursting from the side of the mountain, but Mr Ishihara said he thought the impact of the eruption would not be that serious.

The Sendai nuclear power station, run by Kyushu Electric Power and located on the same island, resumed operations last year after being shut down, along with all of Japan's nuclear plants, after a 2011 earthquake and tsunami triggered a meltdown at the Fukushima nuclear plant.

Japan lies on the Ring of Fire — a seismically active horsehoe-shaped band of fault lines and volcanoes around the edges of the Pacific Ocean — and has more than 100 active volcanoes.

The Sakurajima volcano experiences hundreds of small eruptions every year.

Reuters