The father of former Hamilton sailor and environmentalist Peter Bethune has not heard from him in 10 days, and believes the Japanese whalers holding him are refusing to allow him contact with the outside world.

Peter Bethune is expected to be arrested by the Japanese Coastguard when the ship on which he is being detained arrives in Japan later this week.

Mr Bethune boarded the Japanese whaling vessel Shonan Maru 2 in mid-February in an effort to make a citizen's arrest of its captain and present him with a $3 million bill for replacement of his hi-tech craft, the Ady Gil, destroyed in a collision with the Japanese ship in January.

Peter Bethune's father Don told the Waikato Times that while the Bethune family had not be able to speak to Mr Bethune for more than a week, they took some comfort from the fact Sea Shepherd's captain Paul Watson had informed them Mr Bethune was not "physically restrained in any way".

Mr Bethune understood his son had access to showers and three meals a day, and was being "well looked after" by the Japanese whalers, who were transporting him to Tokyo.

"We are relieved that message (from Mr Watson) got through, but we haven't heard anything further in about 10 days," he said.

Don Bethune said he understood the New Zealand High Commissioner to Japan was "taking an interest in Pete's situation".

Mr Bethune said the prospect of Peter Bethune facing a foreign court was "slightly worrying".

But Sea Shepherd had given a commitment to the Bethune family the conservation organisation would fund Peter Bethune's legal defence.

`It will be underwriting all legal expenses," Mr Bethune said.

He doubted if the family could do much to influence the situation, and did not have the resources to head to Japan to support Peter Bethune.

The Bethune family had confidence in the New Zealand Government in assisting Peter Bethune.

Mr Bethune said the family had received "spontaneous messages of support, often from quite unexpected places" in the wake of the incident.

"The moral support for the Bethune family is absolutely positive, right the way through," he said.

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