The head of the International Air Transport Association (IATA) on Tuesday urged the European Union to delay rolling out a carbon tax on air travel next year, warning it could provoke trade wars.

"Non-European states see it as a direct attack on their sovereignty," the IATA's director general Tony Tyler told a forum on international relations in Montreal.

"That is easy enough to understand when European states essentially would be pocketing taxes for emissions by non-European carriers over the sovereign territory of non-European states," he explained.

Tyler warned the tax could provoke a trade war.

"No one wants a trade war. It seems to me states are clearly preparing for the possibility... but it is not inevitable," said the head of the aviation group that represents some 240 airlines comprising 84 percent of total air traffic.

The European Union imposed the tax with effect from January 1, but no airline will face a bill until 2013 after this year's carbon emissions have been tallied.

The EU has said the carbon tax will help the 27-nation EU bloc achieve its goal of cutting emissions by 20 percent by 2020 and that it will not back down on the plan.

The EU argues that the cost for airlines is manageable, estimating that the scheme could prompt carriers to add between 4.0 and 24 euros ($32) to the price of a round-trip long-haul flight.

Over two dozen countries, including China, Russia and the United States, have opposed the EU move, saying it violates international law.

Tyler said the EU should embrace a "global approach" to airline emissions and thus allow the International Civil Aviation Organization (ICAO), a UN agency, to set a solution. Such "cannot be achieved in Brussels," he said.

The ICAO is scheduled to release at its next general assembly in 18 months market-based proposals to curb aircraft emissions. "What they (the EU) could do is to defer the implementation of their scheme" until then, Tyler told AFP.