Japanese whalers could hunt a regulated number of minke whales in its coastal waters, and take many more whales in the North Pacific, under the plan.

In exchange Japan would agree to one of two offers: either to phase out scientific whaling in the Antarctic entirely, or to impose an annual Southern Ocean limit.

The proposal was hammered out in secret by an International Whaling Commission drafting group of six nations, which includes Australia and Japan, at a meeting in Britain last month.

The International Fund for Animal Welfare said Australia had become part of a dangerous drift towards commercial whaling in the 21st century.

"This is Whalergate," the global director of the fund's whale program, Patrick Ramage, said yesterday.

"We have had growing concerns about the talks under way behind closed doors in the IWC. Those concerns are increased by the leaking of this secret plan.

"We would hope and expect Australia to take the lead in ending scientific whaling. What we're looking at here is not a creative and sustained effort to make Japan step away. It's a cobbling together of ingredients."

A spokesman for the Environment Minister, Peter Garrett, said Australia remained strongly opposed to commercial whaling in all its forms, including so-called scientific whaling.

"While Australia is actively participating in these deliberations, the process at this stage is one of discussion," the spokesman said. "We do not expect that every view or option put forward … will reflect the Australian Government's position."

The IWC, under the chairmanship of the US appointee William Hogarth, has held a series of meetings over the past two years to try to bridge the global schism over whaling.

The Federal Government has taken part in the Hogarth process believing it offers the best chance of ending Japanese whaling in the Antarctic. The Prime Minister, Kevin Rudd, said last week that Australia and other countries were directly engaging with Japan on the issue.

For its part, Japan is continuing to warn that the IWC is so polarised there remains a high possibility of the process collapsing.

"This year is a moment of truth for the IWC," Japan's chief negotiator, Joji Morishita, said last week. "This is almost a final try."

But the six-nation drafting group seems to have gone much further down the track towards agreement than was thought.

Mr Hogarth was to unveil this document at an IWC meeting in Rome in early March, before a possible vote at the organisation's annual meeting in Madeira in June.

It sketches out an overall five-year plan for the resolution of many contentious issues. But at its heart is what the drafters said was a "direct link" between scientific whaling and Japanese coastal whaling.

"For example, if an option to phase out scientific whaling in the Southern Ocean was agreed, a larger quota could be assigned for coastal whaling provided that all annual quotas are consistent with the advice of the Scientific Committee," the document says.

An "interim quota" of Japanese minke whales would last for five years, and be regulated to protect the endangered "J" stock in the Sea of Japan.

On scientific whaling, the first option provides for no kill of humpback or fin whales in the Southern Ocean, and a phasing out of scientific whaling for minkes, reducing by 20 per cent each year to zero after five years.

Japanese whalers have struggled to approach their annual self-awarded "scientific" quota of up to 935 minke whales in recent years, and the first option does not identify a starting quota for the phase-out.

However, the document says: "It is anticipated that the phasing out of scientific whaling in the Southern Ocean could be associated with increases in the number of whales taken in the Western North Pacific."

The second option provides for an unspecified "sustainable" limit on minke and fin whales still hunted in the Antarctic, countered by minke, sei, Bryde's and sperm whales taken in the Western North Pacific.

At the same time, the documents say the global moratorium on commercial whaling "will remain in effect". Mr Ramage said: "That seems to rank alongside 'there is no recession' and 'there are [weapons of mass destruction]' as an Orwellian approach beyond belief."

The Opposition environment spokesman, Greg Hunt, said it was a gross betrayal of the Australian public for Mr Garrett to be working on a secret deal to resume Japanese commercial whaling. "This is completely unacceptable. Australia's position must be: 'No way. No whaling, whatever'."

Speaking from the ship Steve Irwin, the Sea Shepherd leader Paul Watson said his group would continue its zero tolerance approach to whaling in the Southern Ocean.

"Thanks to us there has been a reduced catch for the last three seasons. Japan has no right to kill whales in these waters and we considered their activities to be blatantly illegal and intolerable."