Japanese authorities are refusing to cooperate with a Maritime New Zealand investigation into a collision between whaling boats and anti-whaling protesters, according to a government source.
It comes as an Australian report was found to be inconclusive , after also being hampered by Japanese non-compliance.
Japan's government declined to participate in the Australian investigation, saying any information it had might be needed for an inquiry by its own authorities.
The anti-whaling trimaran Ady Gil, part of the Sea Shepherd fleet, and the Shonan Maru 2 collided in remote Antarctic waters on January 6, slicing the protest boat in half.
The incident has turned into an international "he says, she says" debate.
Anti-whaling protesters claim it was a deliberate ramming that sliced their multi-million dollar boat in two.
"It's perfectly clear that the Shonan Maru altered course sharply to starboard moments before the collision," says Bill Watson, Sea Shepherd Conservation Society.
The Japanese though, say it was a consequence of continual sabotage.
Either way the collision left one New Zealand crewman with broken ribs and five others were almost thrown overboard.
An Australian fact finding report into the collision was inconclusive, unable to determine who was to blame.
"The report's tailor-made for a do nothing government, it's a do nothing report with no spine or backbone or even decent new info in it," says Bob Brown, Australian Green Party leader.
The Australian Maritime Safety Authority says Japan refused to answer its questions, Japan indicating it wanted to "avoid any prejudice to possible Japanese investigations."
"So basically Japan is allowed to refuse to comply with an official investigation into a crash within Australian waters and that's ok, somehow that doesn't seem right to me," says Watson.
The Japanese investigations include those that lead to criminal charges currently being faced by Ady Gil skipper Pete Bethune for boarding the Shonan Maru 2 as part of the anti-whaling protest.
The trial gets underway later this month and his wife Sharyn says his letters show he is upbeat.
"I think as long as he gets out in July he'll be fine, if he has to stay there for any length of time it probably will affect him."
But she is worried about what Japan's continued silence will mean for her husband's future.
"There should be something to make them put all the cards on the table and show what they're playing with," she says.
A hand that could force her husband behind bars, for up to fifteen years.
