A former US Marine helicopter pilot, who finds the whaling fleet so Sea Shepherd protesters can stop the hunt, says he has been denied a visa to join the activists in Australia.

Chris Aultman, who won official praise for his work on a polar search last summer, has been held up in Los Angeles as the countdown begins to this year's conflict.

Refused entry ... Chris Aultman. Credit:Sea Shepherd Conservation Society

Mr Aultman said by email that he had come to Australia for the past six years on an electronic travel authority visa, but this time was placed on hold, and then declined.