The EU's second highest court Friday annulled a European Commission decision to authorise a genetically modified potato developed by German giant BASF, saying it had not followed proper procedure.

The Commission "departed from the rules of the authorisation procedures," the EU's General Court, which sits below the European Court of Justice, said in a statement.

In 2010, the Commission cleared BASF's Amflora potato, genetically modified for industrial and animal feed use, after a general request from the company and a specific cultivation request from Sweden.

Hungary, supported by France, Austria, Poland and Luxembourg, challenged that decision and sought an annulment on the grounds that the modified potato was unsafe.

The Commission gave its approval after the European Food Safety Authority (EFSA) said in a consolidated opinion in 2009 that it believed Amflora posed no threat to human health or the environment.

However, the Commission did not submit the EFSA's view, which included dissenting opinions, to two advisory committees made up of representatives from EU member states which would normally have been consulted.

On that basis, the General Court said the Commission, the EU's executive arm, was at fault.

"If the Commission had complied with those rules, the result of the procedure or the content of the contested decisions could have been substantially different," the Court said.

But, "because the Commission significantly failed to fulfil its procedural obligations, the General Court has annulled the contested decisions," it said.

A spokesman for the Commission said it took note of the judgement and its consequences would be analysed.

An appeal was technically possible, the spokesman said, but that would be for the Commission's legal services to decide.

BASF, the world's biggest chemicals company, said the Court's ruling included no opinion as to the scientific merits of Amflora.

The decision fully justified its decision to focus on other markets outside Europe, it said, adding that it had dropped work on Amflora.

In January, BASF said it would no longer seek European approval of its other GM potato products in the face of stiff popular resistance.

GM products, widely used in animal feed and industry, spark very sharp differences.

Supporters say they are essential to ensure food security and do no harm while opponents argue that they pose a serious threat and could have damaging unintended consequences if they spread in the environment.