Japan's whaling fleet leaves on Tuesday for the Antarctic for a three-month, scaled-down hunt, the government said, despite protests from opponents who say Tokyo has not proved that whales need to be killed for research.

Monday's announcement comes days after Japan submitted its final plan to the International Whaling Commission after the commission's scientific committee said earlier this year it was not convinced that whales needed to be killed for research on whale stock management and conservation.

The expedition will be the first since the International Court of Justice ruled last year that the hunts were not truly scientific, forcing Tokyo to revise its Antarctic whaling plans. Last year, Japan did go to the Antarctic, but its research did not involve killing any whales.