The Turnbull government has been criticised for inaction over whaling after allegations Japanese ships have killed whales in Australian waters.

Environment Minister Josh Frydenberg said on Monday he was “deeply disappointed” by images released by anti-whaling group Sea Shepherd that showed a fresh minke carcass aboard a Japanese whaling ship inside Australia’s whale sanctuary off Antarctica.

He said the government would continue its efforts to stop whaling through the International Whaling Commission.

But Sea Shepherd managing director Jeff Hansen said the government’s response was inadequate.

“‘Deeply disappointed’ is really not good enough,” Mr Hansen told The New Daily.

“When they were in opposition, the government said there was blood in the water and a blind eye in Canberra. Now they’re in power and there’s still blood in the water and a blind eye in Canberra.”

Mr Hansen demanded the government send a vessel to the Southern Ocean to monitor Japan’s whaling fleet, noting a recent poll that indicated support for such a measure.

“We [Sea Shepherd] are the only ones there between the harpoons and the whales,” he said.

He also urged the government to take legal action through the International Tribunal for the Law of the Sea.

The government has been urged to do more to stop whaling. Photo: Sea Shepherd

Mr Frydenberg’s comments came two days after Japanese Prime Minister Shinzo Abe met with Malcolm Turnbull in Sydney.

The two leaders spoke about the proposed Trans-Pacific Partnership and defence issues, but also reportedly discussed whaling.

On Sunday night, Sea Shepherd released footage and images shot from a helicopter that showed a slaughtered minke whale on board the Japanese whaling ship Nisshin Maru.

Sea Shepherd activists onboard its MY Steve Irwin boat alleged that they had encountered the Japanese ship in Australian waters.

“When we found them and they saw us, they were scrambling to put a tarp on the dead whale,” Mr Hansen said.

“They were in the Australian Whale Sanctuary so they know it’s illegal.

“We know that the fleet is heavily funded by Japan … it’s Shinzo Abe’s whaling fleet. But our Prime Minister just passes it off as if they’re discussing the weather.

“We have the resources that Japan needs. We should not be on our knees to Tokyo.”

Sea Shepherd activists say the whale was quickly covered with a tarp. Photo: Sea Shepherd

Mr Frydenberg said Australia had a strong record on combating the practice.

“Australia is opposed to all forms of commercial and so-called ‘scientific’ whaling,” he said.

“It is not necessary to kill whales in order to study them.

“We will continue our efforts in the International Whaling Commission to strongly oppose commercial whaling and so-called ‘scientific’ whaling, uphold the moratorium on commercial whaling, and to promote whale conservation.

“No country has done more to try to end whaling than Australia.”

Japan says its whaling program is for scientific purposes. Photo: Sea Shepherd

The slaughtered whale spotted on Sunday is the first documented since the International Court of Justice ruled in 2014 that Japan must stop whaling, according to Sea Shepherd.

Japan announced a scaled-down version of the program after the ruling, which it says is for scientific research. That claim is rejected by most other nations.

Between 2005 and 2015 Japan caught about 3600 minke whales, according to the International Court of Justice.

Labor spokesman Tony Burke said the government had been “absent on this issue for too long”.

“Despite the international court ruling that Japan’s whaling is illegal, whalers have continued their trade under the guise of ‘scientific research’ – a claim found by the court to be entirely false,” he said.

Greens Senator Nick McKim said Mr Turnbull had “bottled it” by not taking up the issue more forcefully with the Japanese Prime Minister, describing this as “tacit approval” of whaling.

The Japanese Embassy in Canberra declined to comment.