Christchurch police are making inquiries, to see if there are any unreported incidents of historic sexual offending linked to St Bede's College

A former staff member of the school has been charged with offending against three students who boarded at the Catholic school two decades ago.

He's facing four charges of assault on a boy aged between 12 and 16, and three charges of indecent assault on a male aged over 16.

Detective Senior Sergeant Karen Simmons says a number of officers and detectives are working on the case, and investigations remain ongoing to determine if there is any further offending

She's assuring victims they're safe to report offending in confidence.