Three-quarters of Japanese whale meat has remained unsold at auction, an activist group says.

The Tokyo-based Institute of Cetacean Research (ICR) has organised 13 rounds of public auctions since October to boost consumption of whale meat, but 909 tonnes of the 1,212 tonnes offered have not sold, according to a report on Wednesday by the Dolphin and Whale Action Network.

"We could not achieve the results we had anticipated," an ICR official was quoted by the Kyodo News agency as saying.

The institute said the bids submitted by wholesalers and food manufacturers were often lower than the lowest price it had set or that no bids were submitted at all.

Japan's much-criticised whaling is a money-losing operation because most Japanese don't eat whale meat, but vested interests are keeping it running, critics say.

Whaling is subject to a 1986 international moratorium and is opposed by many other countries including New Zealand where activists have run a long campaign to stop whaling altogether.

Japan officially halted commercial whaling in 1987, but it has used a loophole in the moratorium to continue under the premise of scientific research.