The European Public Prosecutor's Office said on Thursday it is investigating Spain's Equality Ministry and the Court of Auditors as part of a probe into suspected fraud involving European Union funds used to buy electronic monitoring bracelets for gender-based violence cases.

The investigation concerns EU funds allocated for electronic monitoring devices used to ensure compliance with precautionary measures and restraining orders imposed in gender-based violence cases, the EPPO said in a statement.

Equality Minister Ana Redondo said her ministry had been cooperating fully with European prosecutors for months and that she was confident the money had been spent correctly. She said the current contract had addressed shortcomings detected in the previous system and warned against undermining a programme that she said had helped protect more than 4,000 women.

Earlier this year, Spain changed the provider of the tracking devices worn by men accused of violence towards former partners after a data glitch impeded an unspecified number of criminal trials.

The EPPO, the EU's independent prosecution office, did not disclose further details on the investigation, which it said was being supported by Spanish police. The office investigates crimes affecting the EU's financial interests.