Australian Opposition Leader Tony Abbott on Tuesday challenged the federal government to take legal action against Japanese whaling.

"It's still not too late," Abbott urged.

Abbott said the Australian government should forge ahead because it promised to do so before the last federal election.

"I challenge the prime minister either to take Japan to the International Court or to admit .. that was always just an empty gesture," he said.

Japanese vessels are in Antarctic waters with plans to hunt more than 500 whales this summer.

There is an international ban on commercial whaling but it is legal for any country to hunt whales in the name of scientific research.

Some legal experts said Australia could claim the whaling activities constitute commercial whaling, so are illegal.