A Nelson shop owner who was confronted by a group of local children wielding a metal bar and a knife says police are powerless to stop such behaviour.
Aucks Hoogeveen, who has run the Washington Valley Store for 11 years, says the children, aged between eight and 12, have caused trouble before.
He says he pushed them outside the store and one of them threatened a customer with a knife.
While police came quickly, Mr Hoogeveen says, they won't be able to stop the children returning.
He says some of them have fathers in prison and police could not locate their mothers.