A cooling system at one of Fukushima’s nuclear plants has been restarted after a 7.3 magnitude earthquake and a small tsunami hit Japan’s northeast coast.

Tokyo Electric Power Co told national broadcaster NHK the water cooling system in reactor number that that supplies cold water to the nuclear rods in Fukushima’s Daini power plant had stopped.

Early reports show the cooling system is back online.

The power company is monitoring other reactors at Onagawa and the sister plant in Daiichi, Fukushima which was the centre of a catastrophic nuclear disaster in the 2011.

In March 2011 a 9.1 magnitude quake struck the east coast of Japan resulting in a tsunami which destroyed the emergency cooling units in the Fukushima nuclear power plant reactors. This caused reactor four to overheat leading to three nuclear meltdowns.

It was the worst nuclear disaster since 1986 Chernobyl catastrophe.

The earthquake was the most powerful quake in Japan's history with almost 16,000 people and hundreds of thousands left homeless.

Tokyo Electric Power Co told local media they have found no damage in any of their reactors but will continue to monitor the situation.