A leading charity has warned that the world's existing stockpiles of the anti-venom Fav-Afrique will expire in June.

Doctors Without Borders says the world will run out of one of the most effective treatments for snakebites next year, risking the lives of tens of thousands of people, mostly in developing countries.

In a statement issued on Monday, the medical charity warned that existing stockpiles of the anti-venom Fav-Afrique produced by Sanofi Pasteur will expire in June.

The company stopped producing the anti-venom last year and has since switched to making a rabies treatment instead.

"We are now facing a real crisis," Dr Gabriel Alcoba, the charity's snakebite adviser, said in a statement.

The aid group, also known by its French acronym MSF, said there would likely be no alternative to replace the Sanofi Pasteur snakebite treatment for at least two years.

A spokesman for Sanofi Pasteur said the pharmaceutical was driven out of the market by competitors selling cheaper products and that they announced in 2010 they would stop making anti-venom.

"It's very strange that (health officials) are only realising this problem five years later," said Alain Bernal, a Sanofi Pasteur spokesman.

He said the company has offered to transfer the anti-venom technology to others but "nothing has materialised yet".

About 5 million people are bitten by snakes every year, including 100,000 deaths and several hundred thousand others who suffer amputations or other disabilities. When it's available, the anti-venom treatment typically costs $US250 to $US500 ($A362 to $A723).

Before a meeting this week in Switzerland, MSF called for international agencies to ensure that snakebite treatment is available where needed.

MSF said that the World Health Organisation should play "a leading role" in solving the problem and criticised the agency for labelling the issue as a neglected condition.

However, WHO said it does not have an internal snakebite expert and there is no formal program within the organisation to address it.