There has been anger over South Korea's plan to hunt whales.
Killing whales to eat has been banned since 1986 but officials say they want to hunt them for scientific research.
Many people say whales should be protected and not be hunted at all.
Australia's Prime Minister Julia Gillard said: "We are completely opposed to whaling, there's no excuse for scientific whaling."
It's not clear how many whales South Korea are planning to catch. They say it's so they can learn more about the animals, what they eat and how they migrate.
Australia and New Zealand are worried that South Korea may use scientific research as a cover to hunt whales for money.
Their neighbour Japan is already allowed to hunt whales for scientific reasons, but the meat is often sold on to restaurants and shops.
South Korea says it has the right to hunt whales for research and will stick to the rules set out by the International Whaling Commission.