Smoke from hazard reduction burns is set to clear across Sydney with windy conditions and higher temperatures leading the RFS to cancel further controlled burning.
Reduction operations on Saturday resulted in hazy conditions and poor air quality, but the Bureau of Meteorology is forecasting winds up to 45 km/h in the city on Sunday and a maximum temperature of 28C.
As a result "the majority of planned burns have been postponed due to the forecast winds and warmer temperatures," an RFS spokesman told AAP on Saturday evening.
Sydney's air quality was poor on Saturday with the east experiencing very poor conditions later in the day.
But the Office of Environment and Heritage is forecasting fair air quality on Sunday.
RFS crews will be patrolling the hazard reduction burns that took place on Saturday in Wollemi National Park, Blaxlands Ridge, Colah Heights and the Wakehurst Parkway at Warringah.
They'll also be battling fires yet to be brought under control north of Port Macquarie at Clybucca and Korora.
Sydneysiders with respiratory problems were warned on Saturday to take precautions in the hazy conditions created by the controlled burns outside the city.
Dr Ben Scalley, the director of NSW Health's Environmental Health Branch, said those most at risk were children, older adults and people with heart and lung conditions.
"If you have asthma you should follow your asthma action plan and take your relieving medication where necessary and if symptoms get worse, seek medical advice," he said in a statement.
The RFS insists hazard reduction burns are needed "ahead of a potentially dangerous fire season".
Not since 2002 has Australia experienced such a dry winter with high fire loads fuelling the bushfire potential, the BOM said this week.
Northern NSW is facing "near record values" in terms of the bushfire risk.