Police are investigating the unexplained death of a person in Christchurch - reportedly a teen who died on the street.

Emergency services were called to Opawa Road, in the southern suburb of Opawa, on Tuesday morning.

"Police are making inquiries to determine the circumstances of what happened, Detective Senior Sergeant Greg Cottam said in a statement.

"We are appealing for anyone who was in the area this morning who has seen anything that may assist police, to contact us."

The dead person was a 17-year-old male and it wasn't clear if it was an assault or a medical event, Stuff reports.