The eastern suburbs of Sydney were brought to a 90-minute stand-still by a major power outage which left 45,000 homes and businesses without electricity.

Power was cut about 11:30am to homes and businesses in Randwick, Bondi Junction, Bondi, Kensington, Waverley, Double Bay, Woollahra, Bronte, Bellevue Hill, Clovelly, Coogee and Rose Bay.

Power supplier Ausgrid said the outage was caused by an underground cable fault at the Double Bay zone substation.

NSW Fire and Rescue crews rescued people who were trapped in lifts in the densely populated area.

When elevators at Prince of Wales Hospital stopped working, doctors, nurses and anaesthetists joined kitchen staff in carrying trays up 10 stories to patients.

Authorities said 23 traffic lights were out in the affected area and police warned people to be cautious on the roads — however, all intersections are now operational.

Sydney is in the middle of a heatwave, with temperatures hitting 35.2 degrees at Sydney Airport just before midday.

Earlier today, NSW Premier Gladys Berejiklian was talking up the state’s “resilient” power grid.

“We’ve seen other states struggle, such as South Australia and Victoria,” she said.

“But of course we always keep a watch and brief.”

Patients at the Sydney Children’s Hospital at Randwick were sitting in the dark for a short time before power was restored.

Kensington Public School sent a message to parents saying the school has lost power and that phone lines were down, but lessons had not been interrupted.

The Revive Clinic in Double Bay said it had been forced to turn away two clients.

The clinic, which specialises in hair restoration and injectables such as Botox, posted on social media that clients had to be rescheduled for 3.00pm.

However, they later clarified that just after midday the lights suddenly came on said it would be “business as usual”.