A teenage boy has been stabbed and two others assaulted at an out-of-control party near Queenscliff on Sunday morning.

Police were forced to break up a party of more than 300 held on the sand dunes near Point Lonsdale after receiving reports of robberies and assaults taking place.

A 17-year-old boy was attacked by a group just after midnight. He was stabbed and assaulted and was taken to hospital with non-life threatening injuries.

Two 16-year-old boys were also approached by a group of men. They were threatened at knifepoint and assaulted before having their phones stolen.

One boy from Newtown was taken to hospital with minor injuries while the second boy from Jan Jac was assessed on scene by paramedics.