A 41-year-old woman is in hospital with critical head injuries after an assault in her Christchurch home early on Sunday morning.

The woman was taken to hospital after police were called to an address in Worcester Street, Linwood, just east of the city centre, about 1am on Sunday.

She is currently in a critical condition in the Christchurch Hospital intensive care unit.

Detective Senior Sergeant Corrie Parnell says a man is assisting them with enquiries after presenting himself to police.

"Although we are speaking to a number of people in connection with the incident, we are not looking for any other individuals at this point," Det Snr Sgt Parnell said.

"We believe the man was known to the victim."

He said police also wanted information about the movements of a green Toyota Camry sedan, registration ST8323, in the 24 hours prior to the assault. It may have been in the Sumner and Waimakariri River areas as well as Christchurch.