The European Union has tightened controls on imports of Chinese rice products after a growing number of shipments were contaminated by unauthorised genetically-modified rice, the EU said Tuesday.

The EU has decided to require Chinese authorities to provide a report on all rice consignments before export, instead of the current random checks.

The move was in response "to an increasing detection of products contaminated with unauthorised genetically-modified (GM) rice," the European Commission said in a statement.

The decision was based on an audit from a mission in China carried out by the commission's Food and Veterinary Office in March and persistent reports about GM rice in the EU's Rapid Alert System for Food and Feed.

"The mission's initial findings indicate an uncertainty as to the level, type and number of GM events, which may have contaminated rice products originating in, or consigned, from China," the commission said.

"They also indicate that there is a risk of further introductions of non-authorised genetically-modified organisms in such rice products."

Chinese rice products contaminated with the unauthorised GM rice Bt63 have been notified through the EU's alert system since September 2006.

A control system was set up in April 2008 to prevent the introduction of such rice in Europe but GM rice was detected again later on.

The new measures will be reviewed in six months.