Police arrested 110 people on Australia Day, including four alleged members of the Bra Boys who are accused of assaulting a man in Sydney's east.

Officers said a pot plant was thrown on to a balcony of a Tamarama home about 3.15pm and a 38-year-old who asked four men to leave was kicked in the head and knocked unconscious.

He was taken to the Prince of Wales Hospital.

Four men - two aged 20 and the others aged 24 and 21, and all alleged members of the Bra Boys - were charged with affray.

Police were out in force across the state on Australia Day under Operation Ambara, headed by Assistant Commissioner Mark Murdoch.