A global deal to free trade was in doubt after talks by major trade powers to save the World Trade Organisation"s (WTO) Doha Round collapsed.

But Australian Trade Minister Mark Vaile says the suspension of the talks does not represent the end of the multilateral system that governs commerce around much of the world.

"This is not the end of the multilateral, rules-based trading system," Mr Vaile said.

Mr Vaile says it is likely that WTO member countries will increasingly pursue grievances on trade issues at the WTO"s dispute-resolution panels, now that the Doha negotiations are suspended.

Ministers from the so-called G6 - the United States, the European Union, Australia, Brazil, India and Japan - had made a last ditch bid to overcome differences on reforming world farm trade, which lies at the heart of the round.

Brazilian Foreign Minister Celso Amorim said he was "disappointed and concerned" and said "of course there is always a risk of some unravelling" of the progress achieved in the negotiations to date.

"The silver lining is that all those who spoke continue to be committed," he said.

The United States said that the EU and other WTO members that it calls "protectionist" had not done enough to lower farm tariff barriers to allow it to move further on subsidies.

"We won"t give up ... (but) unfortunately it became clear that a "Doha Light" is the preferred option of some," US Trade Representative Susan Schwab said.

Diplomats say failure by the G6, who have already made several "last ditch" bids for a deal, would leave the 149-state WTO without enough time to complete the complex details of a global free trade treaty by the end of the year.

The end-year deadline for concluding the Doha Round has been dictated by the 2007 expiry of special US presidential powers to negotiate on trade.

The crisis recalled a similar breakdown in 1990 during the previous round of free trade negotiations - the Uruguay Round. That round, launched in 1986, was only finished in 1993.