The whaling season has begun with a Japanese hunting vessel leaving port for the Southern Ocean, Greenpeace claims.
The conservation group said the ship Nisshin Maru left the port of Innoshima on Monday.
Greenpeace activists unfurled a banner saying "whaling on trial" as the ship left port.
Japan has set itself a target of about 1,000 whales in the Southern Ocean.
Greenpeace International Whales coordinator Sara Holden said the ship left port quietly, without the usual fanfare that accompanies the start of the season.
"Constant pressure on Japan's whaling industry by both Greenpeace and the international community has reduced the fleet to sneaking out of port in a fog of crisis and scandal, desperate to avoid attention," Ms Holden said.
Greenpeace will not send out a ship to trail the Japanese fleet, but rival conservation group Sea Shepherd plans to.
The Australian federal government sent out a ship last season, but has not said if it will do so this season.
The government has announced it will spend $A6 million ($NZ7.1 million) on non-lethal whale research to show the Japanese you don't have to kill whales to study them.
