More than 12 fire units are on the ground attacking the firefront and protecting containment lines and are being supported in the air by two helicopters and Large Air Tanker which has been dumping fire retardant on to the blaze throughout the day.

Aaron Hall, from Sancrox-Thrumster Rural Fire Brigade, said the fire is burning in coastal heath, melaleuca and tea tree. The high oil content of both species means they produce large amounts of black smoke.

"It looks far more dramatic than it actually is," Mr Hall said.

"It is in inaccessible area though and we can only get our smallest units in there.

"The fire has moved south from Crestwood (since Saturday) but it has expanded in size. We will continue to monitor the weather and the direction of the wind."

The Large Air Tanker is working to strengthen containment lines on the north western edge of the fire to protect homes into the evening.

Read more: Waterbombing efforts overnight to contain Crestwood blaze | photos, video

The Lakes Innes Nature Reserve, including access to the historic ruins off The Ruins Way, is closed and there is no access to the Googik Track.

Fire crews are controlling traffic in the Crestwood and Innes Lake residential estates and are requesting that only residents seek access to and from these areas.

Residents in the area are likely to experience increased smoke and embers and should continue to monitor conditions

Read more: Fire crews strengthen containment lines at Crestwood

The Rural Fire Service (RFS) says smoke is impacting on Ocean Drive and in the general area around the Lake Innes Nature Reserve.

RFS liaison officer Jonty Bruce says the Crestwood Road bush fire is continuing to impact the wider area.

"Lake Innes Nature Reserve is now closed and we don't want people in or around that area," he said.

"Smoke is continuing to impact on Ocean Drive and the general area..

"At this stage no property is in immediate threat.

"It is continuing to burn in that nature reserve," he said.

The North Coast Public Health Unit is advising Port Macquarie residents to take health precautions while smoke from the weekend's Crestwood bushfire continues to affect local air quality.

Fine smoke particles affect the human respiratory system and can aggravate existing chronic health conditions by penetrating deep into the lungs and entering the blood system.

Director of the North Coast Public Health Unit, Paul Corben, said the particles can cause various health problems such as itchy or burning eyes, throat and nose irritation and illnesses such as bronchitis.

"We urge people with chronic respiratory or cardiac conditions to be aware of the health effects of exposure to bushfire smoke and to take steps to protect their health," Mr Corben said.

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