Japan's ruling and opposition parties have agreed to establish a panel with strong powers to investigate the causes of the disastrous Fukushima nuclear power accident.

Lawmakers said the 10-member panel will have broad authority to summon witnesses and demand the submission of documents.

Agreement to set up the panel came from the ruling Democratic Party of Japan and four opposition parties, including the main opposition Liberal Party of Japan.

A bill to establish the panel is expected to be passed during the current session of parliament.

The Fukushima Daiichi nuclear power plant suffered core meltdowns in three of its six reactors after a March 11 tsunami knocked out cooling systems at the plant.

Engineers are still struggling six months later to bring the plant to a state of cold shutdown.

Radiation from the plant has leaked into the air, sea and ground, affecting drinking water as far away as Tokyo. Tens of thousands of people still are unable to return to their homes within a 20-kilometer radius of the plant.

The plant's failure is considered the world's worst nuclear disaster since the Chernobyl accident in 1986.