Japan's transport minister Saito Tetsuo has visited the northernmost prefecture of Hokkaido, where a tour boat went missing on Saturday.

The Coast Guard is searching for the 19-ton Kazu One, which had been cruising off the Shiretoko Peninsula in eastern Hokkaido with 26 passengers and crew members on board.

On Sunday, Saito instructed staff at Shari Town, who are investigating the accident, to quickly conduct a special audit of the operator of the vessel.

He urged them to consider the feelings of the family members of the missing people, and to provide as much support and information as possible.

Saito also met the family members, who asked him to rescue their loved ones as soon as possible.

The ministry says that the boat caused two accidents last year, including one in which it ran aground. The ministry gave administrative guidance to its operator.

Saito told reporters that his ministry will work to verify how the three accidents were related through the special audit.