TORONTO - Access to clean, potable water will become a growing source of international tension unless governments take steps to protect the world's supply, experts are warning ahead of a water security conference in Toronto.

Water has turned into an "urgent security issue" as urbanization, population growth and other forces place increasing strain on natural resources, the experts said.

More than a dozen environment and policy experts are to gather this week for a three-day conference to discuss problems affecting the world's water supply.

A panel moderated by former Prime Minister Jean Chretien and two other former heads of state will draft recommendations to help governments counter those threats.

"We know that water is a possible problem between many nations in the world," Chretien said in an interview Sunday.

Even in Canada, which has the world's largest supply of freshwater, water remains a controversial issue, particularly regarding exports to the U.S., he said.

So far, governments have managed to resolve those tensions "reasonably well" through diplomatic channels, "but we see some dangers, so we want to talk about it," he added.

Experts will also look at how water affects energy, development, the environment and public health.

"Urgent actions need to be taken" to fight water-borne illnesses, which kill roughly 3.5 million people each year, said Zafar Adeel, director of the United Nations University's Institute for Water, Environment and Health in Hamilton.

Other issues, such as water conservation, require long-term solutions, said Adeel, one of the experts attending the conference.

"But we need to start thinking about these things right now," he said.

The conference coincides with World Water Day on March 22.

The panel's findings will be presented to the InterAction Council at its annual meeting in Quebec City this May.

The council includes 37 former heads of state and aims to advise current world leaders on emerging global issues.

Chretien is the council's co-chairman, along with the former chancellor of Austria, Franz Vranitzky, and the former president of Nigeria, Olusegun Obasanjo.