The Maribor police have arrested five people suspected of putting into circulation large amounts of counterfeit euro banknotes forged by an Italian criminal organisation.

The arrests are the culmination of a year-long investigation, which ended last week.

Five suspects have been apprehended, three men and two women. One of them is a Serbian citizen, four are Slovenian, the police told the press on 16 October.

The head of the Maribor police investigators Stanko Vidovič said the five are suspected of putting counterfeit banknotes into circulation in Slovenia and other EU member states, where they were sold for around a third of their face value.

The suspects collaborated with a group of Italian criminals who counterfeited the banknotes worth 20, 50 or 100 euros.

Fake euro banknotes seized from a criminal ring by Maribor police. Photo: Gregor Mlakar/STA

"The counterfeit notes were used in shops, petrol stations, casinos, online purchases and so on. The criminal organisation was careful and well organised," Vidovič said, noting that the counterfeited notes were of extremely high quality.

During the investigation police seized some 2,800 counterfeit €50 notes and 390 fake €100 notes, which altogether amounts to nearly €181,000, along with €21,800 in illegally obtained cash.

The Slovenian police also helped their Italian counterparts in locating two sites in Italy, where the money was being counterfeited.

Some €9 million worth of banknotes originating from the same series of counterfeit notes, which are no longer in circulation, were used in the EU, said Vidovič.

Three of the suspects are also suspected of having been involved in migrant smuggling, two of them of drug trafficking, and one of them of illegal arms sales.