"The Doha Round at this moment of the crisis exiting is a vitally needed, and to be frank, a very low cost global economic stimulus package," Pascal Lamy told participants at an economic forum in Bahrain.
"Estimates suggest that the implementation of this round... would inject to the tune of 300-400 billion dollars a year into the global economy," he told participants at the Bahrain Global Forum.
The Doha Round negotiations launched in 2001 were due to be concluded in March but previous deadlines have been repeatedly missed.
The talks have focused on dismantling obstacles to trade for poor nations by striking an accord that will cut agriculture subsidies and tariffs on industrial goods.
Discussions have been dogged by disagreements over issues including how much the United States and the European Union should reduce aid to their farmers and the extent to which developing countries such as India, China and South Africa should lower tariffs.