New South Wales police have charged five members of a Sydney family over a brawl in which seven officers were injured.

Police were called to a house at Bankstown overnight after reports of a loud argument between a couple, their 21-year-old son and 18-year-old triplets.

Officers say they were leaving when one of the sons king-hit a policeman in the face.

Other family members allegedly set upon the officer.

His colleagues came to his aid and a brawl broke out. Seven police were injured.

Three were treated in hospital for bruises, concussion and a bite wound.

Police say the mother was also taken to hospital with a concussion, along with one of her her sons who was complaining of sore ribs.

The father and children have now been charged with offences including affray, assault and resisting arrest.

The mother has been issued a Court Attendance Notice.