A person has been taken to Christchurch Hospital in a critical condition after an assault in Yaldhurst overnight.

Senior Sergeant Kerry Joyce said police were called to Hasketts Road at about 12.30am.

When police arrived they found a person critically injured.

Police believe those involved knew each other and are investigating what happened.

A St John spokesperson told chrislynchmedia.com an ambulance was sent to the scene.

The crew assessed and treated the patient before taking them to hospital in critical condition.

Police guarded the scene overnight and were due to examine it.

Photos sent to chrislynchmedia.com show police photographers at the scene and a bag lying on the road.