Japan's Fisheries Agency said Wednesday it plans to refit the factory ship used every year on its Antarctic whaling expeditions, in the hope of getting at least another decade's service.
The ageing 8,000-ton Nisshin Maru needs a major overhaul, the agency said, but stressed the refit will be finished in time for this season's hunt.
"As research whaling is important, we'd like to conduct major repairs (on the ship) so that it can be used for at least 10 years," said Tatsuya Nakaoku, the official in charge of whaling.
The agency is studying with shipbuilders how long the refitting will take but "there is no possibility" that Japan will miss the voyage this year, he told AFP by telephone.
Whales are caught by relatively nimble harpoon ships that bring their catch back to the larger Nisshin Maru, where the mammals are butchered and processed, before being chilled.
The Fisheries Agency's comments came after a report in the daily Asahi Shimbun on Wednesday which said it was considering abandoning its controversial mission this season because of the refit.
The Asahi said the idea of there being no hunt this year had met with opposition from politicians, afraid a disruption for even one year would make Japan look "weak-kneed".
Japan's whaling mission departs in November, or later, and comes home in spring the following year.
Commercial whaling is banned under an international treaty but Japan has since 1987 used a loophole to carry out "lethal research" on the creatures in the name of science.
It has infuriated Australia and New Zealand, which say it is a fig leaf for commercial whaling. The Japanese fleet is pursued every year by anti-whaling group Sea Shepherd.
Japan claims the hunt is necessary to substantiate its view that the world had a robust whale population. But it makes no secret of the fact that whale meat from this research ends up on dinner tables and in restaurants.
Anti-whaling activists have cut the number of animals Japan was able to harpoon to 267 in 2011-2012, less than a third of the intended haul.
In the preceding season, Japan cancelled the hunt after killing only 172 whales because of harassment by environmentalists.
Explore further: NOAA's Marine Debris Program reports on the national issue of derelict fishing traps