Japan said Tuesday it has cut its Antarctic whale-catch quota by two-thirds in a move it hopes will convince international opponents it is conducting genuine scientific research on expeditions in the region.

The International Court of Justice -- the highest court of the United Nations -- ruled in March that Japan was abusing a scientific exemption set out in the 1986 moratorium on whaling.

The court said the controversial programme, which sees taxpayer-subsidised Japanese boats harpooning the huge mammals and then selling on their meat, supposedly as a by-product, was a commercial hunt masquerading as research.

Judges said any nation that wanted to avail itself of the scientific exemption had to show why it was necessary to kill whales to do the research.

Japan cancelled its 2014-15 Antarctic hunt after the ruling, but said it intends to resume "research whaling" in 2015-16.

In the new plan submitted to the International Whaling Commission (IWC) and its Scientific Committee, Japan has set a new annual target of 333 minke whales, down from some 900 under the previous programme, the government said in a statement.

This level of catch is "necessary" to obtain information on the age of the population, information Japan says it needs to allow the setting of "safe levels of catch limits" and to ensure sustainability.

Tokyo also defined the research period as 12 years from fiscal 2015 in response to the court's criticism of the programme's open-ended nature.

"We will explain the new plan sincerely so as to gain understanding from each country," Minister of Agriculture, Forestry and Fisheries Koya Nishikawa told reporters.

Japan killed 251 minke whales in the Antarctic in the 2013-14 season and 103 the previous year, far below its target because of action by activist group Sea Shepherd.

Tokyo also conducts hunts in the name of science in the Northwest Pacific, where it killed 132 whales in 2013, and off the Japanese coast, where it caught 92.

The world's whaling watchdog IWC agreed this year to toughen scrutiny of Atlantic hunts, but rejected a bid to expand protection in the South Atlantic, as it struggles to balance traditional hunting claims with conservation.