Firstly, I thought it was an Australian territory where the whaling santuary is and only four countries have recognised it (all ones who have other claims over Antarctica). Japan has never recognised the claim nor the Ross Dependency claim by New Zealand if that is where whaling occurs also. Why should they? Japan also thinks it contravenes the ICRW too.
Argentina, Chile, the U.K., Norway, Australia, France and New Zealand all have claims over Antarctic waters. Of these claims, the only areas that I'm aware of that are in dispute between these parties, is a discrepancy of area rights between Argentina, Chile and the U.K. which have overlapping claims. No other country has claimed the lands that New Zealand has claimed (off of their countries recognized land mass).
Although Japan does not officially recognize the claims of Australia and New Zealand, they signed the Antarctic Treaty in 1959 and ratified it in 1961. This recognizes the International Whaling Commission as the authority responsible for whaling.
Chronology
9 Jan 1841 Ross Ice Shelf and Victoria Land claimed
for Britain.
23 Jul 1923 Antarctica between 150°W to 160°E officially
annexed by Britain.
30 Jul 1923 Claim transferred to New Zealand
(Ross Dependency).
20 Jan 1957 New Zealand's permanent base in Antarctica
(Scott Base) opens.
1 Jul 1996 New Zealand Antarctic Institute, later named
Antarctica New Zealand, established.
Few international countries dispute the legality of the claims made, based upon the traditional right of conquered lands which form the basis of the make-up of all current countries.