A 65-year-old woman suffered facial injuries after two intruders hit her with a plank of wood overnight.
Three people were assaulted in the violent home invasion in Kaka Point, south of Balclutha, police said.
The woman was now being treated at Dunedin hospital.
Two men entered the woman's home about 6pm intending to rob her. When the woman attempted to confront the men they hit her with the wood, police said.
Two members of the public, aged 55 and 65, were also assaulted by the men as they left the property.
Police were searching for the offenders, described as Maori or Polynesian, aged between 18 and 20 and about 1.7m tall. Both were described as slim/muscular builds.
One of the males was wearing a dark blue hooded top, blue jeans and black shoes.
Police asked that anyone who might have seen the men contact the Balclutha police station.