Conservation groups are calling on the International Whaling Commission (IWC) to abandon a proposal that would overturn a global moratorium on commercial whaling.

A group of IWC nations is meeting in Washington to negotiate a way forward for the deadlocked regulatory whaling body, ahead of the annual whaling conference in June.

IWC members including Australia, New Zealand and the US are considering a deal that could overturn a 24-year ban on commercial whaling in return for Japan cutting its quota of whales killed in the name of science.

But Mick McIntyre from the group Whales Alive says the negotiations have gone too far and countries such as Australia must stop the deal from going ahead.

"This compromise proposal certainly has momentum, and that's incredibly worrying," he said.

"Now that they're getting to the point of talking about how many whales to kill, we ask the question, how did it get this far?

"We need to stand tough, work very hard to convince our other allies that we need to stop this compromise in its tracks."

Mr McIntyre says the deal undermines whale protection.

"This isn't about working to create a deal that allows whaling. This is about working to stop whaling," he said.

"Any compromise that is talked about at this meeting is just unacceptable."

The proposal needs a three-quarters majority vote to go ahead. A number of IWC nations are yet to declare their position.