NSW Police Commissioner Andrew Scipione and one of his deputies, Nick Kaldas, are being investigated by the Police Integrity Commission following allegations of improper conduct.

The investigation was prompted by three complaints made by former NSW Police officer Richard McDonald, who now lives overseas, Fairfax Media reports.

He alleges Mr Scipione misled the public and the NSW parliament about the number of serving police officers with criminal convictions and that he had “inappropriate discussions” in relation to the matter with NSW Ombudsman Bruce Barbour.

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Mr McDonald also complained that Deputy Commissioner Kaldas “disclosed confidential information” to former NSW Police officer Larry Cook through emails.

Mr Scipione told Fairfax on Friday that “NSW Police cannot make comment on any PIC investigation” while Mr Kaldas simply replied, “I deny any wrongdoing”.

Earlier this year Mr McDonald found out under freedom of information laws that 437 serving police officers had criminal convictions.

At the time, Mr Scipione said that in most cases those officers would have been convicted of a low-range drink-driving or similar offence.

But further information showed officers had convictions for fraud, stealing, break and enter and serious assaults and most of those with drink-driving convictions were in the mid-to-high range.

The NSW Police Professional Standards Command found complaints on the matter made to it by Mr McDonald were not sustained.

The PIC had since launched an inquiry, with officers travelling to Thailand in October to interview Mr McDonald, and also interviewing Mr Cook in Queensland, Fairfax reported.