Police were called to a teen's house party in Reservoir on Saturday night after a group of gatecrashers caused a disturbance at the property.

The birthday party was interrupted when gatecrashers arrived at the Edwardes Street property.

Police said that four uninvited guests showed up to the party, however, some witnesses said they believed there were more.

Between 50 and 70 teenagers were invited to the party.

The woman who lives at the property, who did not wish to give her name, was hosting the party for her friend's 16-year-old son. She said the gatecrashers came from the parkland area at the back of the house, kicking in the fence and entering her backyard.