European Union officials on Monday authorized a Polish ban on the use of around 700 types of maize seed, including 16 genetically modified varieties, which had been cleared for sale throughout the EU.

The European Commission said the Polish ban was justified because the corn varieties had a long growing cycle that would prevent the crop ripening in the Polish climate.

The 25 EU nations unanimously voted to back the Polish ban in March. Biotech products remain controversial across Europe, where many see them as potential health and environmental risks.

In February, police removed about 30 environmental activists from the entrance of the Polish prime minister's office after some of them chained themselves to railings to call for a ban on imports of genetically modified organisms.

Poland has said it would try to prevent the cultivation of all GM crops in the country, a move also being considered by Luxembourg, Greece and Austria.