Kiwi scientists have thrown their weight behind an international committee calling Japan's whaling 'unscientific'.
Japanese whalers are back in the Southern Ocean, aiming to kill 333 minke whales this year.
Now, 30 members of the International Whaling Commission's Scientific Committee (IWC-SC) have jointly-signed a letter saying the science behind Japan's whaling has not passed a reasonable standard of peer review.
The signatories include principal scientist at the Ministry of Primary Industries Rohan Currey.
The letter says Japan has ignored the IWC-SC's opinions and is proceeding to kill whales under a self-determined quota.
The committee members are calling on the IWC to develop a scientific review process that gives more weight to the opinion of referees than proposers.
Scientists from New Zealand universities have backed the open letter, sharing the committee's frustration.
Otago University zoology Professor Liz Slooten said scientific whaling projects were usually designed poorly, and lacked a testable hypothesis.
"Scientific whaling has a woefully poor record of publishing its results. Most reports are unpublished, not peer reviewed and/or irrelevant," she said.
"A lack of performance criteria makes it virtually impossible to determine whether the research has succeeded or failed."
The IWC has a clause allowing member states to self-issue permits to kill whales for research.
Although many scientists have adopted non-lethal methods to study whales, Japan makes use of the IWC permit clause, says Auckland University scientist Dr Rochelle Constantine.
"This recent correspondence is an indication of how frustrated many members of the IWC committee have become with Japan ignoring advice from multiple robust scientific reviews of their research; it is now considered a waste of time," she said.
In 2014, the International Court of Justice ruled that Japan's decades-old whale hunt in the Antarctic should stop, prompting Tokyo to cancel the bulk of its whaling for the 2014/2015 season.
But the Japanese Fisheries Agency notified the IWC in November that Japan will resume whaling in the 2015/2016 season under a revised plan.
The plan, which calls for cutting annual minke whale catches by two-thirds to 333, is scientifically reasonable, the agency said in a document filed with the IWC.
Japan began what it calls scientific whaling in 1987, a year after an international whaling moratorium took effect.
It has long maintained that most whale species are not endangered and that eating whale is part of its food culture.
The IWC-SC's letter has been published in this week's edition of Nature.