There is a large police presence at a medical incident in Christchurch this afternoon.

Emergency services responded to an incident on Barrington St, Spreydon, at about 3pm. About four detectives arrived on the scene half an hour later.

Officers were seen speaking with a man on the street who appeared stressed and agitated. The man was pacing on the footpath and then sitting against a fence as police spoke to him.

A woman was seen being escorted out of a property and into a police car.

Fire and Emergency NZ (Fenz) confirmed it was responding to a medical event in Christchurch.

Detectives at a house on Barrington St, Spreydon, Christchurch, this afternoon. Photo / George Heard

Emergency services respond to what they called a "medical event" on Barrington St, Spreydon. Photo / George Heard

A Fenz spokesman said they were helping St John Ambulance and sending one fire truck from the Spreydon station.

A spokesman for St John Ambulance confirmed they responded to an incident on Barrington St.

However, he referred all questions to police. The Herald has approached police for comment.