Militant conservationist and Sea Shepherd founder Paul Watson will join this year's campaign against Japanese whalers despite an Interpol notice for his arrest, the group said Friday.

The Canadian national has not been seen since he skipped bail in Germany in July on charges stemming from a high-seas confrontation over shark finning in 2002 but he has pledged to lead the fight against the harpoonists.

The Sea Shepherd Conservation Society is due to kick off its annual campaign against the whalers on Monday, with four ships and more than 100 international crew readying for the southern hemisphere summer pursuit.

"It is expected Captain Paul Watson would appear in command of one of the vessels when the action begins," said Peter Hammarstedt, captain of the Sea Shepherd's Bob Barker vessel.

The environmentalists begin their campaign Monday with the Steve Irwin, previously captained by Watson, leaving the southern Australian port of Williamstown skippered by Indian Siddharth Chakravarty.

The Bob Barker, currently in Sydney, is due to leave later in November, while Sea Shepherd has not revealed the location of its two other ships, new mystery vessel the Sam Simon and the Brigitte Bardot.

"The plan is for our fleet to meet the whaling fleet in the North Pacific off Japan," Hammarstedt said in a statement.

"We are planning to take the battle pretty much up to Japan itself.

"We are keeping the location and identity of our new vessel, the Sam Simon, a secret with our hope that the first time the whalers see the Sam, is when she comes into view on the slipway of the factory processing ship, the Nisshin Maru, effectively shutting down their illegal whaling operations."

The Japanese whalers usually set off around December, with Sea Shepherd ships departing Australia to harass them in the Southern Ocean soon after.

This year, the activists plan to steam north and head them off early.

"We are going to try and intercept them as quickly as possible, and try to make this the first year they get zero kills," Sea Shepherd's Australian director Jeff Hansen said.

Hansen said he did not know how Watson would join the fleet, saying information was only on a "need to know basis".

But there is a quote from Watson, who claims the charges against him are part of a "politically motivated" attempt led by Japan to put an end to his efforts against whaling, included on the latest statement.

"We have never been stronger and the Japanese whalers have never been weaker, we need to take advantage of our strengths and their weaknesses and we need to bring this campaign home -- to Japan," Watson said.

Watson, who for years has harassed Japan's whale hunt, was arrested in Germany in May for extradition to Costa Rica over the shark finning incident in 2002.

Commercial whaling is banned under an international treaty but Japan has since 1987 used a loophole to carry out "lethal research" in the name of science -- a practice condemned by environmentalists and anti-whaling nations.