Roxon said the government is working to ensure the return of the men, who boarded the Shonan Maru No.2 boat on Saturday night in a bid to stop the vessel tailing the Sea Shepherd Conservation Society's anti-whaling flagship, the Steve Irwin.

The Attorney General said the government is examining legal options for the return of the men to Australia, but said that since the boarding occurred outside Australian territorial waters there is no automatic application of Australian law.

"With the laws governing maritime incidents, it’s clear that the presumption would be that Japanese law applies and we are therefore putting a lot of effort into our diplomatic representations being made to the Japanese Government but we will continue to consider all options."

The case is being treated as being within general international waters. "Our advice to date is that Japanese law will apply because these three men boarded a Japanese boat and we understand why protestors take this sort of action.

"We also, as a Government, want whaling to stop but if people do take action, take the law into their own hands, there are sometimes limited - or there are consequences and sometimes there are limited actions that government can take in response."

The government has not been informed as to whether the Japanese vessel intends to take the men back to Japan.

Roxon said the government is not interested in taking action under Australian law against the men. "I don't have any advice that they're likely to have committed any laws that break Australian laws," she said.

The Australian government will continue to make clear its objection to the Japanese Government about whaling, Roxon said, including taking them to the International Court of Justice to stop the process.