A fallen power line is believed to have caused Monday afternoon's fire in Young.
Fire and Rescue NSW responded to calls of a fire on Nasmyth Street near Quayle Milling about 5.10pm.
Additional Rural Fire Service brigades assisted as the grass fire threatened businesses and homes.
Crews on arrival protected the mill and Metro service station on Nasmyth Street.
More crews arrived and battled the blaze to protect homes across the railway bridge.
Young police, Hilltops Council staff and Essential Energy crews responded as more than 1500 homes and businesses were without power.
According to the Fires Near Me app, the grass fire burned six hectares.
Captain Ryan Terry said onlookers from the public made access to the fire difficult.
"It was a slow moving fire as there wasn't a lot of wind. However what did hinder the efforts of emergency services was people going to look at the fire. I know it can be exciting, however we have big fire trucks which we need to maneuver around. So if people can keep that in mind next time and keep clear that would be appreciated," he said.
"It was brought under control in about 20 minutes. Because of the extreme weather forecast for the next few days we mopped up for about two hours.
"At this stage it looks like it was a power line which has fallen off and sparked the fire.
"We thank Rural Fire Service, Young police, Hilltops Council and Essential Energy for their assistance.
"With hot days forecast we ask everyone to keep an eye out for fires and if they do see one ring 000."
A grass fire in Young on Monday afternoon has been brought under control.
The fire burned through about six hectares between Nasmyth Street and Lovell Street near the railway bridge near Big W, according to the Fires Near Me App.
Police responded to stop traffic using the road under the railway bridge.
Firefighters are monitoring the scene.
Fire and Rescue, Rural Fire Service personnel and police were at the scene.
Meanwhile more than 1500 homes and businesses are without power at 6.15pm.
Essential Energy crews are responding, however there is no estimated time for power to be restored.