PM to be 'upfront' with Japan over whaling

Despite being good friends Australia must be "upfront" with Japan about its disappointment with the decision to resume whaling in the Southern Ocean, Prime Minister Malcolm Turnbull says.

Mr Turnbull will express Australia's concern when he sits down with Japanese Prime Minister Shinzo Abe during a whirlwind trip to Tokyo on Friday.

"We recognise that is a point of difference of opinion but we will, as good friends should, ... be upfront and frank about our differences of opinion, put them on the table and deal with them, seek to resolve them," he told reporters.

Opposition foreign affairs spokeswoman Tanya Plibersek challenged Mr Turnbull to tell the Japanese, unequivocally, that Australia opposed the resumption of whaling and was considering whether further legal action is required to enforce the international ban on commercial whaling in the Southern Ocean.

She flagged there was potential scope to take legal action at the International Tribunal for the Law of the Sea.

"It is up to the government and up to the prime minister in the first instance to express to the government of Japan just how disappointed we are with this resumption of whaling," she told reporters in Sydney.