A Christchurch man has admitted stabbing four-year-old police dog Kosmo.

Joshua Luke Cooper, 29, pleaded guilty to injuring Kosmo in the Christchurch District Court on Friday.

Kosmo received a life-saving blood transfusion from a fellow K9 dog after he was stabbed while responding to a family harm incident in the Canterbury town of Kaiapoi in May.

He sustained a 4cm-long cut to the throat that fortunately just missed his carotid artery, and was flown to the 24-hour vet where he was monitored.

Dog handler Constable Regan Turner previously told Newshub he thought Kosmo was going to die after the incident.

"It's not a feeling I want to experience again," he said.

"Despite me calling his name and trying to get him back to me, he just didn't have enough energy to move.

"They tell me if we found him a little bit later it probably wouldn't be the same outcome. That was my first fear really."

Judge Paul Kellar requested a psychological report of Cooper and remanded him in custody until December 11, Court News reports.

Newshub.