Angry residents in Broken Hill left without power for days are set to meet the premier and demand answers for the debilitating outage.

NSW Premier Chris Minns will travel to Broken Hill on Thursday, after severe thunderstorms that wiped out power lines and faulty generators left locals with minimal electricity for the better part of a week.

On Wednesday, most residents had power, but locals fear it could cut out again before the transmission infrastructure is fixed to reconnect the town to the national grid.

A backup gas-fired generator has been offline for nearly a year, while a second one tripped on Monday under high power demand due to hot weather.

Mr Minns will face unsatisfied locals when he heads to the region, Broken Hill mayor Tom Kennedy believes.

“A lot of people in Broken Hill are just not happy, considering we shouldn’t have gone through this,” he told ABC radio.

“There should have been two generators that would ensure Broken Hill kept its power supply and also the outlying regions that have been several days without power at different times during this disaster.”

Mr Minns has criticised network operator Transgrid for a lack of contingencies, given the generator has been down for almost a year.

An inquiry will be held into the incident, which left about 20,000 customers in Broken Hill and surrounding Outback communities experiencing outages.

Residents have been urged to minimise electricity usage between 5.30pm and 10.30pm, while backup measures are in place.

But Mr Kennedy said it was difficult to live by that direction given sweltering conditions, including a peak temperature of 34C on Tuesday.

“It’s easy to say ‘don’t put the air-cooler on’, then it hits 37C, 38C and people just cannot put up with it,” he said.

“That’s fine for politicians, for Transgrid to say ... (but it’s) very difficult to do, considering electricity is an essential part of life.”

Transgrid said additional generators were installed in the town on Tuesday night and further units were on the way, while a 24-hour rotating shift began on Wednesday to fix power lines.

AAP