Japan could suspend its annual Antarctic whale hunt because the ageing flagship of its fleet needs urgent repair work.
The Fisheries Agency of Japan, which oversees the country's whaling programme, is seeking government funds to carry out extensive repairs and a refit of its main factory processing ship, Japan's Asahi newspaper reported.
The work on the Nisshin Maru could take several months, and the Antarctic whale hunt could not take place without it.
It would be the first time in 25 years that Japan would not engage in the annual whale hunt in the Southern Ocean, which usually begins in November or December.
The 18,000 tonne Nisshin Maru has been on every one of Japan's Antarctic whale hunts which began a quarter of a century ago. Japan says the hunt is carried out for scientific research.
It has been one of the prime targets of Sea Shepherd activists, who last month vowed they would not allow Japan to kill a single whale this year.
The Fisheries Agency has refused to confirm Asahi's report but told Australia's ABC News the ship was in need of repairs, the extent of which would be decided at a meeting later this week.
Greenpeace Japan executive director Junichi Sato responded to the report with a renewed call for an end to government subsidies for Japan's whaling programme.
"This is a unique moment for Japan to back away from the international disgrace its whaling programme causes without losing face.
"Huge sums of money are needed to upgrade the Nisshin Maru and bail out the industry from massive debt.
"We are repeating our demand that the government end subsidies for whaling. We simply do not have the money, and the loss making whaling industry does not have the demand to merit even one more yen."