Interpol has issued an international notice for the arrest of fugitive eco-warrior Paul Watson, famed for his high-seas clashes with Japanese whalers, after he skipped bail in Germany.

Watson's Sea Shepherd organisation was two years ago also involved in clashes with tuna fishermen based in Malta and later faced court action by a Maltese company.

It today denounced Interpol's move as part of a "politically motivated" campaign led by Japan to put an end to his efforts against whaling.

Watson, a 61-year-old Canadian, was arrested in May in Frankfurt on a warrant from Costa Rica, where he is wanted on charges stemming from a high-seas confrontation over shark finning in 2002.

"Following confirmation from German authorities that Paul Watson had failed to satisfy the bail conditions established by the German courts and had fled the country, Costa Rican authorities renewed their request... to issue a Red Notice seeking his detention or arrest with a view to extradition," Interpol said in a statement posted on its website.

"Based on Mr Watson's failure to satisfy the bail conditions set by the German court, and the additional information provided by Costa Rica concerning the underlying charges, it was concluded that a Red Notice could be issued," it said.

Lyon-based Interpol does not have the power to issue international arrest warrants but can request member countries make arrests based on foreign warrants through a "Red Notice".

Watson was detained in Germany for a week in May before being released on bail after paying 250,000 euros ($310,000) and being ordered to appear before police twice a day. But he skipped bail on July 22 and fled the country.

Watson, known to his supporters as "The Captain", is a veteran campaigner whose Sea Shepherd organisation is known for its muscular attacks on Japanese whalers.

Without revealing Watson's location, the organisation denounced Interpol's notice as part of an effort by Costa Rica on Japan's behalf.

"Today's elevation of the attack against our organisation and our founder, Captain Watson, is not unexpected," Sea Shepherd's administrative director, Susan Hartland, said.

"Japan is driving this effort in retaliation for our successful campaigns to stop them from whaling in the Southern Ocean Whale Sanctuary," she said.

"We've cost them millions of dollars and exposed their shame to the world because of their refusal to stop the slaughter of whales in an established sanctuary under the lie and loophole of 'research.'"

The group described as "bogus" Costa Rica's charges of "causing a danger of drowning or of an air disaster", which stem from the use of a water cannon against shark-finners.

In a statement last week, Watson accused Japan of conspiring with Germany and Costa Rica to hunt him down in revenge for his attacks on its whaling operations.

Watson said Costa Rica and Germany had been "pawns in the Japanese quest to silence Sea Shepherd", which has for years clashed with harpoon ships in the Southern Ocean.

He also did not reveal his location in the message.

"I am presently in a place on this planet where I feel comfortable, a safe place far away from the scheming nations who have turned a blind eye to the exploitation of our oceans," he said.