Updated

The head of a United Nations nuclear fact-finding mission says he has no concerns about working with the Japanese government as his team investigates what happened at the crippled Fukushima Dai-ichi power plant.

Michael Weightman, who is also Britain's top nuclear safety inspector, says the mission is receiving full cooperation from the government and answers to all its questions.

The team was organized by the International Atomic Energy Agency and arrived in Japan on Tuesday. The experts met with government officials on Wednesday, including Chief Cabinet Secretary Yukio Edano.

They are to travel to disaster-affected northeastern Japan on Thursday for visits to the Fukushima Dai-ichi power plant and two other nuclear plants.