The Rudd Government's decision to turn its back on the "whale war" in Australian Antarctic waters is irresponsible, Australian Greens Leader Bob Brown said today.

"The collision of a Japanese whaling ship and the Sea Shepherd vessel Bob Barker shows as much courage by Sea Shepherd as it does diplomatic cowardice by Canberra," said Senator Brown.

"The Prime Minister should dispatch a naval vessel to keep the peace.

"Naval surveillance would raise the prospect of the whale killing season ending, without people being killed as well," Senator Brown said.