Peter Bethune knew precisely what he was doing, and the consequences, when he boarded the whaling vessel Shonan Maru 2 to make what fellow-protesters described as a citizen's arrest of its captain.

This was a stunt, presumably cooked up in Fremantle as Mr Bethune licked his wounds after the sinking of his anti-whaling boat, the Ady Gil, last month.

There was never any chance the Japanese skipper would present himself at a New Zealand or Australian port to answer charges of destroying the Ady Gil and what the protesters claim was the attempted murder of its crew, or write a $3 million cheque for the cost of a replacement boat.

Mr Bethune was intent simply on grabbing publicity. He, and the Sea Shepherd Conservation Society, wanted to prompt a diplomatic incident, thereby putting further pressure on the Japanese to end whaling.

It will suit his purposes if he has to stay on board the Shonan Maru 2 until it returns to Japan.

He can hardly complain if the Government has seen through this exercise, and is refusing to play along.

A meeting between the Foreign Minister, Murray McCully, and the Japanese Ambassador has resulted in New Zealand officials being advisedby Mr Bethune that he is fit and being well looked after. The Government need do nomore.

The Prime Minister has called for calm heads to prevail. Strenuous diplomatic efforts are being made to encourage the new Japanese Government to abandon whaling.

The upping of the ante in the Southern Ocean, which culminated in Mr Bethune's stunt, is hardly conducive to those endeavours. Indeed, it could lead to a hardening of Japanese resolve. It would help if Mr Bethune and the Sea Shepherd group were wise enough to know when to take a step back.