Police in Christchurch are speaking to a man after a serious assault early on Sunday morning left a woman in hospital with critical injuries.
They say they were called to an address in Linwood, shortly after 1am.
They found a 41-year-old woman with severe head injuries.
She is in a critical condition in the intensive care unit at Christchurch Hospital.
Detectives say a man has come forward and is assisting investigators with their enquiries.
They are not looking for anyone else in connection with the incident.