Councils can take action if fire pits produce excessive smoke, the NSW Environment Protection Authority says.
The sale of fire pits have boomed in the Hunter and elsewhere, creating more smoke pollution in addition to wood-fire heaters.
Residents have been expressing their anger on social media about fire pits and wood-fire heaters, saying they have a right to clean air.
Some people think they have a right to burn wood, but many hate having to put up with the smoke pollution, which authorities say poses a risk to people's health.
Children, the elderly and people with heart or lung conditions are most likely to be affected.
"Fire pits and barbecues are permitted under the Protection of the Environment Operations (Clean Air) Regulation, so long as only dry seasoned wood, liquid petroleum gas (LPG), natural gas or prepared barbecue fuel (including a small quantity of fire starter) is used," an EPA spokesman said.
"Anything else that causes excessive smoke is not permitted."
The spokesman said the build-up of wood smoke can, on occasion, lead to PM2.5 levels [tiny particulates] that exceed national standards.
"Wood smoke has greater health impacts in cities and centres where population densities are higher, in areas that experience colder winters and heating demand, and in areas that form geographic basins such as Sydney and Armidale."
The EPA said wood smoke led to poor air quality in 2020 in: Armidale (24 days), Sydney (3 days), Hunter Valley (2 days), Orange (3 days) and Gunnedah (1 day).
"This is similar to previous years," the spokesman said.
However, people in areas where wood is burnt often in their streets and neighbourhoods say the problem is far worse than this.
The NSW EPA has published a long list of pollutants from wood heaters that include: benzene, carbon monoxide, formaldehyde, lead, sulfur dioxide and volatile organic compounds.
NSW Health states on its website that "wood-burning heaters make a substantial contribution to air pollution in NSW".
They affect the air quality "inside your home and the surrounding environment".