Japan suffered a major setback on the first day of the International Whaling Commission meeting in South Korea after losing a vote to allow secret ballots.

New Zealand Conservation Minister Chris Carter said from the meeting last night that member countries had narrowly voted against the proposal, 30-27, despite Japan's confidence it would succeed.

"Japan must be furious."

Japan wanted a secret ballot to take pressure off countries making unpopular decisions.

Mr Carter said Nauru, understood to be pro-whaling, had not turned up to the meeting of the 66-member body, while Denmark and Finland voted against secret ballots despite their general support for Japan.

Tuvalu, Kiribati and the Solomon Islands had, as predicted, aligned themselves with Japan, which Mr Carter put down to "promises of aid".

He said Japan was acting "super-aggressive" but members had realised the IWC's integrity would have been at stake if secret ballots were allowed.

The next important vote in the week-long meeting is scheduled for today with Australia's remit, seconded by New Zealand, to condemn Japan's scientific whaling.

Mr Carter said Japan was using a loophole to harvest whales and now wanted to more than double its minke whale kill in the Antarctic to 935, and take up to 50 endangered fin whales and 50 humpbacks.