The owner of a fishing boat in Japan that drifted across the Pacific after getting washed away from its moorings by last year's huge tsunami does not want it back, a Japanese official said Tuesday.

The 65-meter (210-foot) vessel was spotted last week by a Canadian Forces aircraft on a routine surveillance patrol.

A military photo shows the ship, streaked with rust but intact, floating 150 nautical miles off the southern coast of Haida Gwaii islands, some 1,500 kilometres (930 miles) north of Vancouver.

A Japanese coastguard spokesman said the boat belonged to a fishing firm in Hakodate, Hokkaido, and had been anchored in Hachinohe, Aomori, when the tsunami struck.

"The owner told us it is not needed anymore," said the spokesman.

The unidentified owner told Japanese media he had given up hope of seeing the boat.

"I had not dreamed that it would cross the Pacific," the Yomiuri Shimbun quoted him as saying on Monday.

"I have already abandoned my proprietary right. I would like (the Japanese government) to help scrap it by talking to countries concerned."

The vessel is the largest item confirmed to have crossed the Pacific Ocean after the tsunami in March last year, but it is thought to be at the vanguard of a huge swirl of debris ripped from the shore.

Ocean researchers based in Hawaii are monitoring the flotsam from the tsunami, including household appliances, cars and parts of houses, which they earlier predicted would reach western North America early next year.

The Japanese fishing boat is not expected to make landfall for another 50 days, observers said.