Acting Prime Minister Julia Gillard told reporters in Melbourne that there was no reason to ban the Sea Shepherd group's anti-whaling ship, the Steve Irwin, from docking in Hobart, Tasmania, when it arrives next week. Japan had said Tuesday it planned to ask Australia to bar the ship from its ports.

'We have not received an impending vessel request from the Steve Irwin,' said Ms Gillard, who is filling in for vacationing Prime Minister Kevin Rudd. 'Should such a request be received, then the Steve Irwin will be permitted to dock at an Australian port.'

The Steve Irwin is named after the late Australian conservationist and TV personality.

Protesters aboard the ship have chased Japan's whaling fleet for 3,200 kilometres and last month lobbed bottles of rancid butter at the whalers. They are currently around 4,000 kilometres southeast of Hobart.

On Tuesday, Japan - which has described the protesters as terrorists - said it would ask countries where the ship might make port calls to refuse it entry.

'They have obstructed our activities in the past, and their action is extremely dangerous,' Foreign Ministry official Chiharu Tsuruoka said. 'They are like pirates.'

Ms Gillard reiterated her earlier concerns that the Sea Shepherd crew refrain from dangerous activities in the remote and icy Antarctic Ocean.

'That is obviously a dangerous stretch of water. It's very far removed from land,' she said. 'We want people when they are on that stretch of water to conduct themselves in a way which ensures that they stay safe and others are safe.'

Japan has temporarily suspended its whale hunt in Antarctic waters after a crewman apparently fell overboard Monday from one of the vessels in the six-ship whaling fleet. The accident was not believed to be related to the Sea Shepherd protests.

The Japanese fleet plans to harvest up to 935 minke whales and 50 fin whales this year. Under International Whaling Commission rules, the mammals may be killed for research but not for commercial purposes.

Opponents say the Japanese research expeditions are a cover for commercial whaling, which was banned in 1986. -- AP