The historic sex abuse scandal engulfing Auckland's Dilworth School is snowballing

Another man has been arrested in relation to alleged historical sexual offending at the country's richest school.

He's the seventh person arrested over alleged serious offences from the 1970s to the early 2000s, with at least 17 victims.

The 60-year-old has been charged in relation to sexual violation, attempted sexual violation, indecency and indecent assault.

Police say there have been more than 50 calls and emails from the public since the first arrests were announced yesterday.