A teenage boy is among five young men arrested after a party in Sydney's north-west overnight, during which a police van was smashed.

Police say word of the party spread on social media, and 300 people were at the gathering in Winston Hills.

The police and the property owner closed the party down with assistance from the Public Order and Riot Squad who were called to help disperse the crowd from the area.

Police who arrived to shut down the party were allegedly confronted by an drunk 16-year-old boy who assaulted one officer.

He was arrested along with four men in their early 20s.

Police also found the front windscreen of their van had been smashed while they were inside the party.

Three of the men are scheduled to face court in February.