More than 170 countries have agreed on a new international treaty cracking down on the illegal tobacco trade.

Representatives of governments and international organizations meeting Monday in Seoul, South Korea, unanimously approved the pact.

The protocol creates a new global system requiring non-removable tracking codes on each pack of cigarettes. That is meant to make it easier to trace producers and distributors of counterfeit tobacco products.

World Health Organization director-general Margaret Chan, speaking at the opening session of the Framework Convention on Tobacco Control, said Monday that the new pact gives the world an orderly, rules-based instrument for countering and eventually eliminating the international criminal tobacco trade.

The WHO estimates one in ten cigarettes purchased are coming through illegal channels, costing governments more than 40 billion dollars annually in lost taxes.

To be implemented the treaty will need ratification by more than 40 countries.