Japan's whaling fleet has left its home port for another turbulent season in the Southern Ocean, this year courtesy of extra money from the nation's earthquake recovery fund.

Three vessels have set sail from the port of Ishinomaki, in western Japan, with a mission to catch 900 whales over the next three months.

The Japanese fleet will have beefed-up security this year after its last season was cut short by the Sea Shepherd anti-whaling group.

The fleet did not get anywhere near its target last season and Sea Shepherd is hoping for a repeat performance.

But there is anger in Japan and elsewhere this year about the source of new funds for the trip.

The Japan Fisheries Agency says the trip's use of $28 million from the earthquake recovery fund is legitimate, because it is taken from the government’s own quake recovery fund.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 3 minutes 31 seconds 3 m 31 s Earthquake funds given to Japanese whalers Download 1.6 MB

Greenpeace Japan executive director Junichi Sato says it is a massive stretch to link whaling to the earthquake.

"It's not related to the recovery at all," he said.

"It is used to cover the debts of the whaling program because the whaling program itself has been suffering from big financial problems."

Three Sea Shepherd vessels are preparing to depart from Albany and Hobart in the next 10 days to disrupt the whaling.

The Bob Barker will leave from Hobart and two other Sea Shepherd ships will join them Albany. ( ABC, Michael Dalla Fontana )

The group's founder, Paul Watson, says this summer is bound to get ugly in the Southern Ocean.

"I did ask the Australian Government for assistance," he said.

"I think the responsible thing considering the number of Australian citizens involved would be to send a vessel down to keep the peace, but they don't seem to be too interested in that.

Federal Environment Minister Tony Burke says whaling in the Southern Ocean is wrong and unlawful but there are no plans to send a Customs or Navy vessel.

But Mr Burke says Australia is taking legal action in the International Court of Justice to stop the whaling.

"Unfortunately as with all legal action it takes longer than you want it to," he said.

"We've taken the toughest line of any country in the world by launching this legal action. We're throwing everything at it."

Mr Burke says spending earthquake recovery money on whaling is not appropriate.

"I don't think it's appropriate for any money to be spent on Japanese whaling," he said.

"Regardless of where money's coming from our position is really simple. There's no shades of grey here.

"We believe the Southern Ocean is a whaling sanctuary and all whaling that occurs there is wrong."

Opposition environment spokesman Greg Hunt says the lack of an Australian vessel is a weak response.

"There is a risk of a significant potentially fatal conflict at sea between whalers and protesters and the Government must dispatch a customs vessel by Christmas in order to coincide with the likely arrival of both the whaling fleet and protesters in the Southern Ocean," he said.

Japan say it will have extra security for the trip this year, which is needed to protect a legitimate "scientific" enterprise.

The Japan Fisheries Agency issued a statement to AM saying the Japanese government's aim for the whaling voyage is "to get the scientific data".

The first whales should be caught by the end of the month, with the season to last until March.

Editor’s note: (January 30) inaccurate comments by Paul Watson about international aid being used to fund the hunt have been removed from this story. In fact overseas funds were not involved.