The return of warm westerly winds and higher temperatures across the state this week is set to push bushfire danger back to dangerous levels.
Fire conditions across NSW eased on Sunday, with firefighters gaining the upper hand on two blazes while another remains out of control in the state's north.
The Rural Fire Service has downgraded the alert level to advice for a fire burning in the New England region about 15 kilometres east of Glen Innes.
The out-of-control blaze has burnt more than 9000 hectares but the RFS says the threat to homes has eased and roads are reopening.
But Monday's weather - with a strong wind warning forecast for Sydney, the Hunter, Illawarra, Batemans and Eden Coast, and temperatures pushing 30C - would cause fresh headaches for firefighters.
The Bureau of Meteorology has also issued a hazardous surf warning for the Illawarra coast.
Favourable conditions for firefighting wouldn't return until Wednesday.
"Fortunately today we didn't have as bad a day as yesterday. Most firefighters held on their current containments," an RFS spokesman told AAP on Sunday.
"(Tomorrow), it will be a problem day."
About 12 fires were on Sunday burning out of control across NSW.
In northern NSW's Drake, firefighters were getting control of a blaze which has burnt more than 53,000 hectares but been downgraded to advice alert level.
Fire crews had also gained the upper hand on a bushfire burning in Bees Nest near Armidale which is at advice alert level.
The blaze has razed more than 90,000 hectares and continues to burn on multiple fronts within Guy Fawkes River National Park, Mount Hyland Nature Reserve and Nymboi-Binderay National Park.