BRUSSELS (Reuters) - Belgian judicial authorities said they are investigating former and current NATO staff and have arrested one suspect over possible irregularities in awarding contracts for NATO military equipment.

The Federal Public Prosecutor's Office said in a statement on Wednesday that, as part of an investigation into membership of a criminal organisation, corruption and money laundering, police arrested and questioned two suspects in Belgium on Monday. One remains in custody, while the other has been released.

The arrests were made as part of criminal investigations in Belgium, with offshoots to the Grand Duchy of Luxembourg and Spain, and in the Netherlands - coordinated by the EU agency for criminal justice cooperation Eurojust.

The investigations focus on possible irregularities in awarding NATO contracts to defence contractors for equipment such as ammunition and drones, notably the possible passing-on of confidential information by employees of the Luxembourg-based NATO Support & Procurement Agency (NSPA) to defence contractors.

Belgian prosecutors added that several former or current NSPA employees could be involved and that there were indications that money obtained from the illegal practices was laundered, partly by setting up consultancy companies.

They added that NATO was cooperating with the investigations.

A NATO spokesperson said that, thanks to an investigation initiated by NSPA, law enforcement authorities in a number of countries had arrested several individuals accused of corrupt activities related to NATO contracts.

"NATO is working closely with law enforcement to ensure that perpetrators are brought to justice," the spokesperson said.

Late on Tuesday, the Dutch Public Prosecution office said it had arrested a former Dutch defence ministry employee on corruption charges. The suspect - who was arrested on Monday at Schiphol Airport - was responsible for international purchase contracts.

The man is suspected of having taken bribes in 2023 over the awarding of purchase contracts, together with others, some of them outside the Netherlands.

Two other Dutch suspects - who were not civil servants - were also arrested as part of the case.

(Reporting by Geert De Clercq and Andrew Gray. Editing by Mark Potter)