The European Commission will say next week public authorities cannot ban farmers from planting genetically modified (GM) crops, supporting those farmers who want to embrace the controversial technology.

The EU executive will agree guidelines on Wednesday local time on how GMO crops can be grown along with organic and conventional crops, part of a push to lift the five-year moratorium on GMO crops that is under attack from the United States. 

"A group of farmers in a region can club together and decide not to grow GMO crops but a regional or national government cannot create a GMO-free zone," an EU official said on Friday, adding the freedom of farmers to choose is enshrined in EU law. 

The provincial government of upper Austria has banned genetically modified organisms but the European Food Safety Authority recently said there was no justification. 

The commission will take the final decision on the Austrian case in September.

The co-existence debate is seen by many in the biotech industry as another way for GMO-sceptical countries to postpone lifting the five-year ban on most GMO crops.

It follows the adoption in principal of rules to label all GMO food and feed earlier this month, giving consumers the choice between GM and non-GMO products on supermarket shelves.

But growing GMO crops in Europe still provides a number of headaches.

Who should pay if genetic material is found in organic and conventional crops - the farmer or seed producer?

Green groups and a number of member states want binding EU legislation where the biotech industry would foot the bill, paying for such "contamination".

But the EU executive says that is up to national authorities.

EU farm ministers will discuss the commission's guidelines in September.

"The commission says that member states should check whether some liability laws need to be changed or updated and also look at insurance policies," an EU official said.

Meanwhile, the Piedmont regional government in Italy recently ordered the destruction of 381 hectares of maize fields thought to contain genetic material. 

It is not clear yet who will pay the cost.