Trade Minister Banri Kaieda said Japan's 54 reactors would undergo "stress tests" to determine how well they can withstand major disasters.

Only 19 reactors are still operating, causing a drawn-out energy crisis.Engineers are still working to shut down the Fukushima plant, which continues to leak radioactive material.

Japan was hit by a 9.0-magnitude earthquake - the country's most powerful on record - creating a massive tsunami that levelled towns along the country's north-east coast.

Waves from the tsunami caused back-up generators at the Fukushima Daiichi plant to fail, disabling reactor cooling systems and leading to meltdowns, explosions and radiation leaks.

The plant's operator Tepco has come under heavy criticism for failing to sufficiently prepare for the natural disasters. The crisis has led to great public concern over the safety of nuclear energy.

"The safety of nuclear power plants has been secured, but this is to gain a further sense of security among the people," Mr Kaieda was cited as saying by Jiji Press news agency.

Speaking on television, Mr Kaieda said: "We are planning the stress tests to gain the understanding of local residents. We will get further confidence from the people and will restart operations at some plants."

He did not say when the stress tests would begin; however, he promised there would be enough energy available for the peak usage during the summer months.