More than 100 firefighters are still working to contain a bushfire that threatened several homes near Newcastle.
Newcastle Airport says its operations are back to normal on Sunday after smoke from the Tomago blaze forced its closure on Saturday.
NSW Rural Fire Service Commissioner Shane Fitzsimmons says the overnight weather change has hampered containment strategies.
"There are a 100 firefighters working on that fire to try to get it under control," he told the Nine Network on Sunday.
"There is a lot of work left for firefighters before we bring that fire properly under control."
Water bombing aircraft and more than 60 RFS personnel worked overnight to contain the blaze as it threatened homes.
Mr Fitzsimmons said strong southerly winds were going to be an issue for firefighters in Tomago on Sunday.
He again warned that forecast extremely hot conditions at the end of this week could cause issues around the greater Sydney environment.