Proposals for acceptable contamination limits for GMOs in Europe will "facilitate biotech companies", Green MEP Ms Patricia McKenna has claimed.
She also said the proposals could see unauthorised GMOs introduced into the environment and "conventional crops damaged in the future".
The EU Commissioner for Food Safety, Mr David Byrne, is to table proposals next month for acceptable contamination limits for GMOs in Europe.
A spokesman for Mr Byrne said rules were being introduced with a view to providing consumers with full regulation and full confidence.
Ms McKenna said she was "outraged the commissioner responsible for protecting consumers should envisage such proposals and would put the interests of the GM industry before the interests of public health".
A spokesman for Mr Byrne said the commissioner represented the consumer fully.
Ms McKenna said that "by introducing acceptable levels of GM contamination, the Commission leaves the door open for widespread contamination, and threatens the livelihood of hundreds of farmers in the organic food sector".