An Auckland 1st XV rugby player who was knocked out in a match on Saturday lay unconscious at the side of the pitch for up to 40 minutes before an ambulance arrived, eyewitnesses say.

The long wait for medical treatment for the Liston College player has prompted some supporters to call for ambulance or medical staff to be present at all top-level schoolboy matches.

The Liston player was injured 15 minutes into the game against home team St Kentigern College.

"At halftime they were still waiting for an ambulance," said a St Kentigern supporter, who asked not to be named.