The fire at Waikaraka broke out at about 12.30pm on Thursday, forcing the temporary closure of Whangārei Heads Road and the evacuation of two homes.
Fire investigators have now established that the 14ha blaze started close to the ocean in a steep valley south of the city, between the suburb of Onerahi and Tamaterau Close.
Fire and Emergency incident controller Denis Cooper said fire investigators were still investigating, though they were confident the fire was not deliberate.
He urged residents to check if they needed a permit before lighting fires and to be careful when using barbecues.
“There are pockets of Northland that have a pretty high fire danger rating.
“Whangārei is one of them.”
There are currently restrictions in place for lighting fires in Te Tai Tokerau, so a permit from Fire and Emergency is required for any outdoor fire.
Visit www.checkitsalright.nz to see what the fire restrictions are for your location.
Jenny Ling is a senior journalist at the Northern Advocate. She has a special interest in covering human interest stories, along with roading, lifestyle, business, and animal welfare issues.