Sydney set for a smoky Sunday, with temperatures of 40C predicted for week ahead

Bushfire smoke will again settle across the Sydney Basin, the RFS says, and temperatures are forecast to hit the high 40s in some parts of NSW later this week.

A satellite image showing fires burning across New South Wales, Australia.

A satellite image showing fires burning across New South Wales, Australia. Source: NASA EARTH OBSERVATORY

Sydney is set for another hazy day from bushfire smoke blown across the city, while firefighters are bracing for worsening conditions as NSW heats up.

Temperatures could reach the high 40s in the west of the state by Thursday, the Bureau of Meteorology says.

There were 111 fires burning across the state on Saturday night, 60 of them not contained.

Some 1500 firefighters were tackling the blazes and there was no let-up on the horizon, Greg Allan from the RFS said.

"We will see conditions deteriorate with worsening weather early into mid-next week. We're going to be seeing a lot more higher temperatures across the state," he told AAP.

Places such as Cobar, Broken Hill and Griffith will see temperatures above 40C in the coming week, the BOM said.

Total fire bans have been issued for the Central Ranges, Northern Slopes and North Western areas amid very high fire danger ratings on Sunday and more bushfire smoke will affect the Sydney Basin, the fire service said.

"Smoke from fires burning on the outskirts of Sydney will settle across the Sydney Basin again overnight and tomorrow," the RFS tweeted on Saturday evening.

"There is a possibility the smoke will clear slightly but remaining dense throughout the day.

The Ruined Castle fire in the Blue Mountains remained at watch and act level on Saturday night.

Some 724 homes, 49 facilities and 1582 outbuildings had been destroyed so far this fire season. Six people have died and 2.7 million hectares have been scorched.

Published 15 December 2019 at 7:48am, updated 15 December 2019 at 8:23am