Two senior Japanese officials have warned that there is still a real risk of a catastrophic disaster at the stricken Fukushima nuclear power plant.

Since Japan’s devastating earthquake and tsunami seven weeks ago an army of emergency workers has stabilised two of its six reactors but the other four remain volatile.

The head of the emergency operation at the plant, Masao Yoshida warned: “If a similar strength earthquake or tsunami hits us it would cause fatal damage, especially a tsunami.”

There has been no time to clear away debris around the power station. The emergency teams have been preoccupied trying to minimise the radioactive contamination of the air and the sea.

It is the most serious nuclear crisis since Chernobyl, the world’s worst atomic disaster.

An independent adviser to the Japanese government and special member of the country’s atomic energy commission, Shigeharu Aoyama said: “A big earthquake can strike at any time and we are in the middle of that danger. But we are too focused on how to cool the reactor and how to treat the radioactive water. And although we have 1,500 people working on the problems, we have not built a protective embankment.”

The latest pictures to emerge of the tsunami, triggered by the magnitude nine earthquake are a reminder of the kind of destructive power that was unleashed on 11 March.

The operator of the plant TEPCO has been accused of playing down the potential dangers and ignoring warnings about the risk of an earthquake and tsunami striking Fukushima.