Australia will send a patrol ship and aircraft to monitor Japan's whaling fleet off Antarctica, the government in Canberra has said.
The Japanese whaling fleet left port in mid-November
Foreign Minister Stephen Smith said the vessels would collect evidence to assess whether legal action could be taken against the whalers.
Australia would also lead a formal international protest against Japan over the issue, the minister said.
Japan's fleet set sail in November, aiming to kill over 1,000 whales.
Several nations have condemned Japan's annual hunt, which it says is for scientific research purposes.
Critics say the same research goals could be achieved using non-lethal techniques.
Acting against the whalers was one of the new Labor-led Australian government's election pledges.
Japan says its hunt is too small to affect whale populations
"We are dealing here with the slaughter of whales, not scientific research," Mr Smith told a news conference in Canberra. "That is our start point and our end point."
The Oceanic Viking, a Customs ship, would depart within days, he said, and an Airbus A-319 will soon begin surveillance flights over the fleet.
The two vessels would collect photographic and video evidence of the fleet's activities to help Canberra decide if it could take action against the whalers in international courts, the minister said.
A formal protest would also be lodged with the Japanese government within weeks, he said, without naming other nations involved.
"The Australian government will take all diplomatic measures to seek to persuade the Japanese government to stop the whale slaughter," Australian broadcaster ABC quoted Mr Smith as saying.
The Japanese fleet plans to kill 900 minke whales and 50 fin whales between now and mid-April 2008.
It will also will kill up to 50 humpback whales for the first time since a moratorium was introduced in the mid-1960s. The species had been hunted almost to extinction before the ban.
The hunt has drawn strong opposition from environmental and conservation groups.
Boats from environmental group Greenpeace and the more radical Sea Shepherd group are tracking the fleet. Sea Shepherd says its activists will attempt to intercept the ships.