A homicide investigation began after initial reports of a serious assault and a hammer-wielding man seen "saturated" in blood.
Police said emergency services received a report of a serious assault at an Armagh St property about 7.35pm on Sunday.
A body was located at the address, police said, and a homicide inquiry was under way.
"Soon after, police located a person who is assisting with the investigation."
A man has been charged with murder in connection with the incident, court documents show
Earlier, parts of central Christchurch were cordoned off after reports of a man covered in blood carrying a hammer and running down the road.
The man was later stopped by police on Moorhouse Ave outside the Godfreys Law building, Lynch reported.
Meanwhile, a video sent to Lynch shows a St John ambulance pushing a stretcher into the driveway of a block of flats on Armagh St earlier in the evening.
"Man arrested outside McDonald's saturated in (a lot) of blood all over his clothes from neck down. Not nice. Hoping that everyone involved is OK."
Police urged the public to stay away from the scene.
A police spokesperson said officers were responding to the incident on Armagh St, reported about 7.35pm. "A cordon is in place at the intersection of Armagh St and Barbadoes St. Police are asking the public to avoid the area at this time."
Police said in a statement on Monday morning: "Police believe this to be an isolated incident with no further risk to the public."