The Opposition says the Federal Government should seek an interim injunction to stop Japan from whaling while Australia's legal challenge to the program is ongoing.

Japan's Fisheries Agency has reprimanded five officials for accepting gifts of whale meat from a fishing company operating a government-funded whaling program.

The powerful agency has apologised and vowed to stamp out corruption in the whaling industry.

Opposition environment spokesman Greg Hunt says the episode again reveals that Japan's scientific whaling program is a sham.

"Now we have confirmation that it's a sham, this is the moment the Government can come true on its promise of five years ago to take action on whaling," he said.

"This is the moment for an interim injunction. Any later than this and the slaughter will commence for this season."

Prime Minister Julia Gillard has condemned the actions of the Japanese officials who accepted the gifts.

But she says the revelations reinforce the Government's legal action against Japan's whaling program.

"The Australian Government is completely opposed to whaling. That's why we're taking appropriate action through the international court system," she said.

"We view whaling as unacceptable, so I'm opposed to it in every circumstance, including [this] circumstance."

The Greens also say the Government's legal action will be bolstered by the recent revelations.

Greens Senator Rachel Siewert says the episode demonstrates that so-called scientific whaling is a farce.

"To claim it's scientific whaling - the whole world knows it's not true and this has highlighted it yet again," she said.

"It's such a complete fraud that's been perpetrated on the world to say it's scientific whaling - it's commercial whaling and this highlights it once again."

Six months ago the ABC broadcast allegations by two whaling crew members that officials and crew were illegally taking thousands of dollars worth of whale cuts.

At the time, the Fisheries Agency denied the allegations, but it has now reprimanded officials for taking more than $3,000 worth of whale meat.

"I deeply apologise for this act in which officials took whale meat," said agency spokesman Toyohiko Ota.

"It's an act for which we will lose credibility. We will take prevention measures so it will never happen again."

The original allegations, broadcast on ABC TV's Foreign Correspondent program, undermined Japan's claim that its whaling program was purely for science.

At the time, the allegations were dismissed by the Institute for Cetacean Research, which helps run Japan's whaling program.

The Fisheries Agency also denied officials or crew took whale meat for personal consumption or profit.

Although the agency now admits more than $3,000 worth of meat was taken, Greenpeace and the two whistleblowers believe that is just a fraction of the amount embezzled.

Two Japanese Greenpeace activists, known as the Tokyo Two, are hoping the admission means their convictions for stealing whale meat will be overturned.

They intercepted whale meat in an effort to expose the corruption, but their claims were dismissed by the authorities at the time.