Christchurch City Council's emergency management manager Murray Sinclair said such fires cannot be doused with water, as that can cause further issues.
"Water can increase the heat intensity, similar to the way a compost pile works," he said.
"Yesterday afternoon smoke covered parts of the north east of the city. Fortunately the wind direction changed overnight to southerly, which has resulted in the smoke heading out to sea."
Mr Sinclair says the wind direction has changed this afternoon to a light easterly which could result in the smoke once again covering parts of the city.
Canterbury Medical Officer of Health Dr Alistair Humphrey said the fire is unlikely to cause any health issues at this stage.
"The fire is being fuelled by untreated wood and is not dangerous from a public health point of view," he said.
"However, any kind of smoke is undoubtedly a nuisance and people should avoid exposure where possible by staying indoors and closing windows and doors."
Dr Humphrey said should the fire spread beyond the woodpile, the smoke plume is likely to become heavier and more noxious.
He advised people to stay out of the smoke if possible.
"If that is not possible, close windows and doors to minimise exposure," he said.
The stock pile was destined to be re-used for future building work in the city.
