The parent maize, known as MON 810 and engineered to resist certain insect pests, won approval for growing just before the EU began its biotech ban in 1998 that lasted nearly six years.

Before this, these seeds only had national authorisations issued by France and Spain. But EU law provides for countries to decide whether to allow such seeds on national territory -- although a ban must be approved by EU member states to be legal.

Greece and Poland both used this provision in early 2005.

"On Greece, there was a formal vote which was inconclusive and so the Commission proposal will be examined by the Council (EU ministers) in the autumn," the official told Reuters.

The experts were also due to discuss a similar ban imposed by Poland but postponed a vote since Warsaw had amended its ban to include some non-GMO varieties. The experts would discuss this as two separate dossiers in the autumn, the official said.

"Poland has presented a new request also covering non-GMO varieties. As there is no time limit for this request, the committee agreed to postpone the discussion on both requests until after the summer," he said. "There was no decision today."

In January, Hungary imposed a similar ban on the 17 Monsanto maize seeds but used a different EU law as its legal basis, meaning that its ban must first be assessed by the European Food Safety Authority, whose opinion is due shortly. EU ministers are likely to debate the Hungarian GMO seed ban in the autumn.