A conservation activist says an investigation into claims that Japan bribes small nations for their support on whaling is confirmation of what has been common knowledge for a long time.

Two reporters from Britain's Sunday Times newspaper posed as the lobbyists of a fictional Swiss billionaire and set out to buy votes at next week's International Whaling Commission (IWC) meeting.

Six countries told the reporters they were willing to consider their offer, but the reporters were told they would need to better the aid the countries are already getting from the Japanese.

Tanzania's IWC commissioner is recorded saying that as well as aid, politicians from his country are flown to Japan where they are offered prostitutes.

Geoffrey Nanyaro told the undercover reporters he has never used Japanese prostitutes.

"As a Christian, I live by the Bible, so I never indulge in such [activities]," he said.

Mr Nanyaro says when he visits Japan he is put up in a five-star hotel, and women offering massages often call his room.

"They start by saying you know, do you want massaging, you know, it will be free massaging, you know. Are you not alone there?"

Nicola Beynon from Humane Society International says the undercover investigation adds weight to what environmental groups have long suspected.

"It has been common knowledge for a long time that a number of countries that vote in favour of commercial whaling at the IWC are not actually voting because they genuinely want to see a return to commercial whaling, but they are voting because they are beholden to Japan and Japan's very generous fisheries aid," she said.

"This is confirming what has been common knowledge for a long time and there has been very few occasions where we have had proof of it."

Morocco meeting

The Japanese government is yet to comment on the bribery allegations, which come just a week before the International Whaling Commission (IWC) meets in Morocco.

The meeting will decide whether Japan wins approval for limited commercial whaling.

The decision is a critical one for the Australian Government as well, because if the proposal goes ahead it would destroy the Federal Government's legal case against the Japanese.

Every vote will be crucial. On the table is a compromise deal that could see a return to commercial whaling in exchange for an end to the killing of whales for so-called scientific research.

The compromise is the brainchild of the IWC chairman Cristian Maquieria, but he is sick and will not be at the meeting.

Ms Beynon is sure the deal will be debated without the chairman.

"I think it is going to come to a negotiation over the quotas, so if the quotas are big enough then Japan, Norway and Iceland will want the proposal," she said.

"They will be telling the countries who vote that they have been coercing ... to vote for it and then if those countries combined with some countries who just want a compromise.

"They are tired of the issue. They think if they support this compromise then the issue will die down for them politically. If those countries combine with the pro-whalers then we could see it going through."

Countries that are considering the compromise include the USA.

Opposed to compromise

Australia is vehemently opposed to the compromise and Environment Minister Peter Garrett has launched a YouTube campaign asking for support to end whaling.

"It is highly ironic that we should be having a debate about reintroducing commercial whaling in 2010 - the year proclaimed by the United Nations as the international year of biodiversity," the Minister says in the video clip.

"This is not the time to go backwards by sanctioning whaling for years to come. It is the time to take steps to permanently safeguard the existence of these really important animals."

Outside of the IWC, Australia is taking the Japanese to the International Court of Justice in a bid to prove Japan's so-called scientific research is a sham.

But Ms Beynon warns that the legal case will crumble if commercial whaling is endorsed by the IWC next week.

"If Japan is given a quota for commercial whaling, it means they will no longer need to exploit that loophole for scientific whaling," she said.

"It is the scientific whaling, the exploitation of that loophole that the Australian Government was going to challenge in court, so it would mean that that case becomes moot.

"The government in Japan would be able to continue whaling with a legitimate commercial whaling quota which would just be disastrous."

The proposal for limited commercial whaling would see almost 13,000 whales killed in the next 10 years.

Mr Garrett is describing the meeting as the most important since the IWC banned commercial whaling in 1986.