Christchurch authorities are issuing a health warning for residents about the smoke billowing across the city from the Port Hills fire.
Health officials are warning residents to close windows and doors.
Those at most risk of harm due to smoke inhalation are cigarette smokers, children, the elderly and people with asthma or heart or lung disease.
Dr Alistair Humphrey, the Canterbury Medical Officer of Health, said for most people the smoke will be unpleasant but does not pose a risk to their health.
"However, smoke may irritate the eyes, nose, throat and airways. More serious symptoms include runny or sore eyes, dry or sore throat, sore nose, cough, tightness of the chest or difficulty breathing.
"In healthy people, most symptoms disappear soon after exposure to smoke ends and do not cause long-term health problems."
People who experience trouble breathing, who are coughing or feeling tightness in the chest should call their GP first.
"In an emergency always phone 111. For all other health care needs make your usual general practice team your first call – after hours, and when they’re closed, a team or nurses is ready to take your call. They can tell you what to do and where to go if you need to be seen urgently."