The privacy watchdog has arrested a man on suspicion of revealing personal details of a police officer and his family members without their consent.

The Office of the Privacy Commissioner for Personal Data on Thursday said an online group published a "wanted" person post on social media in July this year, offering a reward to locate the officer who had taken part in an arrest operation in 2019.

On the same day, two "wanted" person notices about the officer and his family members – which included their personal data and some fabricated offences – were then posted as a reply, the watchdog said.

The personal information disclosed included part of the names of the officer and two family members, their photos and the officer's rank.

The watchdog said a suspect, 24, is in custody and the investigation continues.