With a summit in Hong Kong looming at the end of the year, the WTO leader said there has been too little progress in talks.
"I'm concerned on all fronts," Supachai said at the World Economic Forum in Switzerland. "Things have moved, but they've not moved far enough to guarantee that Hong Kong will be the penultimate step to complete the round in 2006."
The WTO sets the rules for global commerce. Its 148 member governments are trying to energize the "Doha Round" of trade talks -- so named because it was launched in Doha, Qatar, in 2001. It aims to slash subsidies, tariffs and other barriers to global trade.