A teen's 18th birthday party spilled into chaos after more than 150 uninvited guests showed up, creating an uncontrolled mess in New Plymouth on Saturday.
Officers were called to Fitzroy Rd at 10.45pm on Saturday after bottles were being smashed, according to Police.
The majority of those in attendance were aged between 15 and 19.
Sergeant Ross Wright told Fairfax it is a great concern when parents aren't aware their children are attending parties and drinking alcohol.
"With most of these kids on social media, they come from the hills to attend...