Interpol has placed the head of the anti-whaling group Sea Shepherd on its international wanted list.
The request to place Paul Watson on the list was issued by Japan.
Interpol has issued a "blue notice", asking international police forces to pass on information about Mr Watson's whereabouts and activities, but it has not issued a notice requesting his arrest.
In April, Japan's national broadcaster reported the country's coastguard was seeking his arrest for instructing his group to obstruct Japanese whaling missions.
The ABC reports the Sea Shepherd leader has harassed the Japanese whaling fleet for the past few years, limiting the number of whales caught for so-called scientific research.
Mr Watson, who is in the United States, says the move by Interpol does not make any sense.
"It's a blue notice which means it's not an arrest warrant, it's just so they can keep tabs on me. But they needn't have wasted their time, they could have just followed our website," he said.
Mr Watson says Sea Shepherd cut Japan's kill quotas in half and the request to Interpol shows anti-whaling protests are having an effect.
"But I can tell them we'll certainly be back down in the Southern Ocean harassing them again in December."
Despite international condemnation, Japan hunts whales under a loophole in a global moratorium.
Bethune back in court next month
New Zealand anti-whaling activist Peter Bethune appeared in a Tokyo court last month on five charges related to his boarding of a Japanese whaling ship in the Antarctic earlier this year. He will reappear on 7 July.
Bethune has been charged with trespass, vandalism, obstructing commercial activity, being armed with a weapon and, most seriously, assault causing injury.
The assault charge stems from allegations Bethune threw tubs of rancid butter onto one of the whaling ships and in the process slightly injured a Japanese crewman.
He pleaded guilty to four of the charges but denied the assault.
If convicted he faces up to 15 years in jail.
