The EU defended its regulations for approving the sale of genetically modified crops (GMOs) yesterday following an important world trade ruling that found they restrict global trade.

The interim ruling by the World Trade Organisation (WTO) found that various EU countries had broken international trade rules by imposing national bans on marketing and growing specific GMOs. It also found that the EU operated a moratorium on imports of GMOs between 1999-2003, according to a 1,000 page judgment leaked to the media.

Experts believe the WTO panel ruling could eventually lead to a relaxation of the rules governing the import and sale of GMO products throughout the EU.

However, an EU spokesman played down the consequences of the interim ruling, which, if affirmed in a full judgment next month, could lead to a suit for damages.

"This interim report is largely of historical interest, rather than of real or practical importance as it does not alter the system or framework within which we take these decisions," said a spokesman for trade commissioner Peter Mandelson.

The three countries that took the case to the WTO - the US, Argentina and Canada - are seeking the removal of existing barriers to the flow of GMO products to Europe.

On a visit to Brussels, US trade representative Susan Schwab urged the European Commission and member states to open Europe's markets further to GMO imports.

"It is unfortunate how this is played out when the EU and individual states have both made it very difficult for farmers and consumers to benefit from these foods," she said.

The WTO panel ruling found that six individual states - France, Germany, Austria, Italy, Luxembourg and Greece - broke the rules by applying their own bans on marketing and importing GMOs. European consumers and governments remain deeply sceptical about GMOs.

The biotech industry, including US companies such as Monsanto and Dow Chemical, were keenly awaiting the ruling in the hope that it would let them boost GMO shipments to Europe.

However, initial reactions yesterday from the member states most opposed to GMO products show that scepticism of GMOs is still high in Europe. Austria, which has banned imports of three GMO maize types, said it would continue to be as restrictive as possible for the time being with regard to GMOs.