Foreign Minister Julie Bishop has pulled back from the Coalition's previous firm commitment to sending a patrol ship south to monitor the whaling conflict this summer.

The Japanese whaling fleet is expected to depart for the Southern Ocean later this year as Tokyo and Canberra await an International Court of Justice decision on Australia's plea to halt the hunt.

Environment Minister Greg Hunt said after that clash, if elected, the Coalition would ''make sure'' Customs was operational in the Antarctic during the whaling season.

But Ms Bishop told the National Press Club in Tokyo on Tuesday that Australia would make a judgment when the whaling season arrived.

''As for sending Australian vessels or Customs vessels, we will make that decision at the time,'' Ms Bishop said. ''It's a question of ensuring that our presence can lead to some appropriate behaviour.''

A spokeswoman for Mr Hunt said the federal government's position was unaltered, indicating it might not be necessary to send a patrol ship south if the ICJ returned a decision favouring Australia in the whaling case.

"There's been no change," she said. "Of course we might have a decision by the international court by that stage."