The Australian government says it is its priority to make sure the three West Australian protesters who have spent more than 24 hours detained on a Japanese whaling security ship were being well cared for.
The three West Australian men boarded the Shonan Maru No.2 in the early hours of Sunday morning off the coast of Bunbury in an attempt to force it to abandon its pursuit of the Sea Shepherd ship Steve Irwin.
Attorney-General Nicola Roxon said the government had been in touch with the Japanese government to find out exactly where the ship was in Australia's exclusive economic zone in the waters off Western Australia.
"Our top priority is to make sure Australian citizens are safe and that they are being well cared for," she said.
She said the boat had not applied to come to shore to offload the three protesters and that they could end up in Japan.
"We know there is a risk protest action will be taken and know there is a risk it might get out of hand in either direction," she said.
Australian Greens Senator Rachel Siewert said yesterday that there was some suggestion the Japanese vessel may have turned off its radar devices, which would usually alert other vessels as to where it is.
The Japanese vessel had been shadowing the Steve Irwin in what protesters believe was an attempt to reduce the ship's impact on interrupting Japanese whaling operations.
Geoffrey Tuxworth, 47, of Perth, Simon Peterffy, 44, of Bunbury and Glen Pendlebury, 27, of Fremantle from the West Australian group Forest Action, boarded the Japanese ship about 16 nautical miles to sea.
Yesterday, the Greens urged the federal government to calm the situation in the Southern Ocean.
Senator Siewert said the activists had stepped in to take action where the federal government had failed.
According to Tokyo's Institute of Cetacean Research, the three men risked being sent to prison in Japan.
In the early hours of Sunday, the trio took a small boat out to sea from Bunbury, for a rendezvous with two small boats from the Steve Irwin.
"The boats approached the Shonan Maru No.2 under cover of darkness and the three negotiated their way past the razor wire and spikes, and over the rails of the Japanese whaling vessel," a Sea Shepherd statement said.
"They came with a message: 'Return us to shore in Australia and then remove yourself from our waters.'"
The three men said in the statement they were taking the stand to prevent the Shonan Maru No.2 from tailing the Steve Irwin back to the Southern Ocean whale sanctuary.
"We as Forest Rescue are insulted and disappointed in our government for allowing the transit of whale poaching vessels in Australian waters," they said.
Senator Siewert said the protesters' actions were a direct result of the federal government failing to act on the whaling situation in the Southern Ocean.
"The Prime Minister needs to pick up the phone and talk immediately to the Japanese PM in order to resolve this issue, these protesters either need to be brought back to an Australia port or the Japanese will keep them on board and take them to Japan, obviously that's an unacceptable situation," she said.
Senator Siewert also wanted the federal government to detain the Japanese vessel or force it to go back to Japan.
"They are not welcome in the southern ocean, the action of sending the Shonan Maru No.2 to shadow the Sea Shepherd was provocative and insulting, insulting that a Japanese vessel supporting whaling operations is in fact in Australian waters, is in fact in an Australian whale sanctuary," she said.
"It's been hanging off our shores, waiting for the Sea Shepherd vessel, the Steve Irwin to leave our waters in order to shadow it back to the Southern Ocean. That is insulting to Australia."
Senator Siewert said while it was not illegal for the Japanese vessel to be in Australian waters for the past three days, the federal government could have taken action to get it out of the area as it was in an undisputed whaling sanctuary in support of whaling operations.
She said the federal government should have sent a ship down to the Southern Ocean to calm the situation long before the situation reached this point.
Senator Siewert said she was concerned about what may happen to the detained men.
Last year a New Zealand man spent time in a Japanese prison following an altercation between an anti-whaling vessel and Shonan Maru No.2.
According to Tokyo's Institute of Cetacean Research, they risk being sent to prison in Japan.
The institute, which conducts the Antarctic whaling program on behalf of the Japanese government, confirmed this was a possibility.
"No decision has been made yet on the fate of the men who boarded the vessel," spokesman Glenn Inwood said.
"But they risk being taken back to Japan to face charges and possible imprisonment.
"What these guys don't understand is that the government of Japan's tolerance for Sea Shepherd and its supporters is extremely low and they risk facing that back in Japan."
Sea Shepherd leader Paul Watson said from the Steve Irwin the ship was heading west towards the open sea with the Shonan Maru No.2 still following.
- with AAP