A homicide investigation has been launched after a teenager's death late last night at an address in the northern Christchurch suburb of Casebrook. 

Detective inspector Michael Ford said police responded to reports of a firearms incident at 11.03pm, but upon arrival the 16-year-old was dead. 

A homicide investigation and scene examination is under way. 

"We are appealing to anyone who was in the area at the time, and can assist with our inquiries, to come forward and speak to us," Ford said. 

A cafe worker on Cavendish Rd in Casebrook, Michelle Counsell, said it was normally a quiet, safe street. 

She had worked at Cosy Cafe in the business complex at the other end of the street for three years, and was shocked to hear about the homicide investigation when she came in to work that morning. 
 
"That kind of thing doesn't ever happen," she said. 

The street is cordoned off while a scene examination is underway. (Photo / Hamish Clark) 

Christchurch city councillor Aaron Keown called Newstalk ZB at around 11.39 last night to report he had driven past a police incident on Cavendish Rd in Christchurch. 

"An incident just happened in Christchurch on Cavendish Rd, between Northcote Rd and Vietches Rd," he told host Marcus Lush. 

"It's closed off by police at both ends. Crime scene tape has gone up and there's police standing there with semi-automatic-style rifles at each end. 

"There's a lot of cop cars here, I can count eight if not more." 

Keown estimated the incident was "very fresh", likely occurring "within the last 10 minutes". 

Police on the scene of the homicide investigation in Christchurch on Saturday morning. (Photo / Hamish Clark) 

Minutes later a second caller to the show said she had also just driven by the Northcote area. 

"There's eight [police] cars, the street before that is cut off and there's a lady [police officer] standing on the street with an assault rifle. 

"Something's going down." 

Anyone with information is asked to contact Christchurch Police on 105 and quote event number P048523046. 

In August a 16-year-old died following a stabbing in the Christchurch suburb of Fendalton. 

More to come.