Fire authorities have warned Sydneysiders to brace for more mornings of smoke haze across the city after bushfire hazard reduction caused air quality to plummet.

Thousands of Sydneysiders were urged to stay indoors on Monday after smoke from weekend NSW Rural Fire Service burns settled on the city overnight.

The NSW Environment Department at one point ranked air quality in east Sydney very poor, recommending those with health conditions to stay indoors.

“If you feel that the air in your home is uncomfortable, consider going to a place with cleaner air (such as an air-conditioned building like a library or shopping centre) if it is safe to do so,” the agency’s Air Quality website said.

Air quality in some other parts of Sydney were ranked “poor”, “fair” and “good”, according to the site.

RFS spokesperson Ben Shepherd cautioned residents more hazy conditions were likely this week.

“It has obviously come to fruition this morning and it could over the next few mornings,” Mr Shepherd told 2GB radio.

Earlier, the RFS said further burns scheduled on Monday could cause smoke haze in Sydney and the Central Coast until mid-week.

Only about 24 per cent of planned hazard reduction burns were done in 2022/23 due to inclement weather making backburning a priority, the RFS has said.

Meanwhile, emergency services continue to battle a huge blaze in the Northern Territory, with fire bans extended near Tennant Creek and fire bombers enlisted from South Australia.

Nearby residents have been warned that smoky conditions are expected to continue for days, as winds of up to 60km/h carry smoke far from the flames.

– AAP