The Australian environment minister, Ian Campbell, says Pacific Island nations risk angering the rest of the world if they support the return of commercial whaling.
An Australian delegation trying to stop the slaughter of whales met government leaders in the Marshall Islands today.
The Marshall Islands has indicated it intends to join the International Whaling Commission, or IWC, but no official decision has yet been made.
It is being lobbied by Japan to join the group of whaling nations.
Senator Campbell says the Marshalls should think carefully about the consequences of its vote at the IWC meeting in St Kitts and Nevis in two weeks, should it attend.
He says if Japan was to win that vote, outrage will swirl around the world, and that is a message for any country joining the IWC.