Police in Kaikoura are worried about a series of attacks on visitors there.
There have been seven assaults in the past 2½ weeks including that of a Czech citizen at 3am on New Year's Day.
Police say he was set upon by five young men who continued kicking him while he was on the ground.
A suspect, aged 15, has appeared in the Blenheim Youth Court and police say further arrests are likely.
Two men will appear in court this month accused of assaulting deputy mayor Neil Pablecheque.