A 19-year-old man has been arrested after an incident last week at a public swimming stream on the Waiotapu Loop Road, near Rotorua.
Police said the incident happened on 11.30pm on 19 December, and the man had been charged with injuring with intent to cause grievous bodily harm and theft.
He is due to appear in the Rotorua District Court on Thursday.
Police said they were still trying to identify and apprehend the other offenders involved.
Anyone with information was asked to call police via 105 and quote file number 201220/7605, or anonymously to Crimestoppers on 0800 555 111.