Three people ended up in Dunedin hospital on Saturday - in varying states of consciousness, hit in the head by thrown objects at a party on Castle Street

Police say an estimated few hundred people were at the party on the infamous Dunedin student street for "Flo-Week" - when students in flats celebrate orientation week.

Sergeant Matt Lee says excess alcohol may have also been a factor for the injured students.

Police have urged students to not engage in risky behaviours like climbing buildings or throwing bottles - during O-Week festivities.