More Poles drive under the influence of illegal narcotics than alcohol, researchers said Thursday.

"According to the initial findings of our study, there are more people at the wheel who're under the influence of drugs than alcohol," Anna Zielinska, an expert at Poland's ITS national automobile transport agency, told AFP.

Working with police, ITS researchers tested 4,000 drivers in selected regions and cities of Poland.

Of those stopped, 2.53 percent were found to have taken illegal narcotics - primarily marijuana and hashish, or amphetamines.

That compared with 1.02 percent who were over the drink-driving limit, which in Poland is 0.2 grammes of alcohol per litre of blood.

Thirteen million Poles hold a driving licence, out of a total population of 38.5 million.

The study indicated that 330,000 Poles drive under the influence of drugs, compared with 130,000 who are drunk.

The ITS research was part of a broad study in 19 of the European Union's 27 member states under the label DRUID - Driving Under the Influence of Drugs, Alcohol and Medicines.