Australia's anti-whaling crusade appears to have been harpooned with fewer ships to take on the Japanese whalers this summer.

Japanese whaling vessels were last season trailed by the Australian Government and conservation groups Greenpeace and Sea Shepherd.

But with the whaling season due to start within the next month, Greenpeace has pulled out and the Government won't say if it will send a ship.

The Greens on Tuesday called on Environment Minister Peter Garrett to take action.

"It is simply not good enough to keep repeating the rhetoric without any resources or action," Greens Senator Rachel Siewert said.

"I urge minister Garrett to take action before we have to sit by and once again watch our endangered whale population slaughtered under the guise of Japanese scientific research."

Opposition environment spokesman Greg Hunt accused Mr Garrett of losing his passion for the fight against whaling.

A spokesman for Mr Garrett said the Government was yet to make a decision about future monitoring of whaling, but staunchly opposed the practice.

"The Government remains resolutely opposed to commercial whaling in any form," he said.

The spokesman said the Government would consider all options to end whaling, including legal action.

AAP