The Sea Shepherd Conservation Society is being sued by millionaire and conservationist Ady Gil over the sinking of his boat three years ago.
The vessel, named the Ady Gil, was hit by a Japanese whaling ship in the Southern Ocean in 2010 and sank.
Sea Shepherd previously claimed that it tried to save the boat, which Mr Gil's lawyer Mark Mazzarella says is worth $NZ5 million.
However its previous skipper, Peter Bethune, has since said that it was deliberately sunk as a public relations stunt.
Mr Mazzarella says Mr Gil wanted to have a legacy in the form of a boat he could support for the next 20 years and was bitterly disappointed when it sank.
He says Mr Gil does not want to ruin Sea Shepherd, as he believes in its work, but does not feel that he is being treated with the respect he deserves.
Mr Mazzarella says Mr Gil is also sad that his father never saw the boat.