Prime Minister John Key says Japan's decision to resume whaling in the Southern Ocean is "appalling" and a show of "bad faith" and he would raise it with Japan's Prime Minister Shinzo Abe if they met in Paris.
Mr Key is at the CHOGM in Malta but heads to Paris early this morning for the COP21 climate talks.
Japan has advised the International Whaling Commission it will resume whaling in the Southern Ocean but has reduced its intended take.
That is despite an International Court of Justice ruling in 2014 that Japan's previous whaling programme was unlawful because it was not for genuine scientific research.
Mr Key said the New Zealand Government had expressed its displeasure to Japan. He would raise it personally with Mr Abe if they met in Paris.