"The Cove", an Oscar-winning documentary on a horrifying dolphin hunt, was stopped from being shown in Tokyo in fear of planned protests by conservatives claiming that the film is anti-Japanese, the distributor said on Saturday.

The film, which was hailed as Oscar's best documentary feature this year, follows a group of activists who fights with Japanese police and fishermen to be able to enter a remote cove in Taiji, southern Japan, where dolphins are hunted.

"The Cove" has provoked activists to threaten street protests.

Unplugged, the Japan distributor of the film, said that it cancelled the screenings at two cinemas in Tokyo this month because demonstrations might distress movie-goers and others.

Another screening was also also called off at one Osaka theatre. However, negotiations to show the movie at 23 venues around the country this summer are underway, a spokeswoman from Unplugged said.

She added that the company has been receiving threats via the phone and protesters have already started gathering outside their offices.

"'The Cove' is absolutely not an anti-Japanese film," Takeshi Kato of Unplugged said in a faxed statement. "I believe a deep and constructive debate is needed about the content of the film."

The doco was directed by Louie Psihoyos, former National Geographic photographer, and features Ric O'Barry, a former dolphin trainer from the "Flipper" television series.

O'Barry, who is scheduled to arrive in Japan on June 8, said that Japanese film-goers should be permitted to view the documentary.

"It's not right that a small minority of extremists could take this right away from them," he said in a statement.

"To do so is a clear threat to democracy."

Although the film was shown during the Tokyo International Film Festival last year, it has yet to be made widely available to the public.

The Japanese government claims that the hunting of dolphins and whales is an integral part of their cultural tradition.

Pete Bethune from New Zealand is currently on trial in Tokyo for boarding a Japanese vessel while trying to stop the annual whale hunt in the Antarctic.