Greenpeace said today it had decided against sending a ship to chase the Japanese whaling fleet in the Antarctic this summer, and will instead concentrate on campaigning in Japan.

The decision not to send the Esperanza south again for a fourth year running comes within days of the expected departure of the fleet for its hotly opposed annual "scientific research" hunt.

It also comes with two Greenpeace anti-whaling activists expected to face court in Japan early next year on charges of stealing a box of whale meat, in a bid to prove it was part of an illegal trade.

Greenpeace Australia Pacific's chief executive, Steve Shallhorn, said the decision not to go south should not be seen as holding out an olive branch towards the Japanese Government.

"There has been no significant movement by Japan so far that's encouraged us to do this," Mr Shallhorn said.

He said it was not influenced by the million-dollar costs of the expedition, because the voyage's high profile in previous years yielded strong donations.

Nor was it influenced by the conflicting plans of rival hardline activists Sea Shepherd, who will go south from Brisbane in December in the ship Steve Irwin.

"We do our own thing," Mr Shallhorn said. "Greenpeace believes the decisive battle to end whaling in the Southern Ocean is in Japan, and that's where we want to focus our efforts."

The Greenpeace activists in Japan, Junichi Sato and Toru Suzuki, spent 26 days in custody before being charged over their investigation into the handing out of free whale meat to the crew of the factory ship Nisshin Maru.