A mild change sweeping NSW is expected to bring some welcome relief to firefighters who've battled more than 40 blazes in scorching heat.
Firefighters were under the pump on the ground and in the air on Sunday after a large bushfire which tore through thick scrub north of Newcastle leapt containment lines.
The blaze burnt 350 hectares of scrub near the Williamtown Airport before blowing south towards Nelson Bay Road.
Residents along Nelson Bay Road between Richardson Road and Medowie Road were warned to be vigilant against embers, after the blaze "spotted" across its southern lines.
Smoke forced the closure of Nelson Bay Road and Medowie Road at around 1pm, with firefighters working to contain the blaze as a "watch and act" alert was issued.
The fire was later downgraded to "advice" level after crews gained the upper hand.
Some 800 firefighters responded to 45 grass and bush fires across the state on Sunday as hot, dry and windy conditions from South Australia and Victoria pushed into NSW.
There were 180 fire trucks on the front line and more than 60 aircraft in the skies as temperatures soared to 40 degrees in some parts of the state.
Total fire bans were issued for eight areas across southern and western NSW as well as the ACT, with severe fire danger ratings in place across the same regions.
An RFS spokesman told AAP all fires were being watched for flair-ups amid hot dry winds, low humidity and very hot conditions on Sunday.
Crews are still working to douse a blaze on the ACT/NSW border which has engulfed about 42 hectares.
Firefighters will stay at the Mt Clear bushfire overnight to monitor any hot spots that may flare up.
No total fire bans will be enforced in NSW on Monday as conditions ease, but there remains a very high fire danger in the state's upper central-west plains.
