The northern Australian city of Darwin has been hit by a major blackout, forcing schools to close and knocking out traffic lights.
The power cut, which was caused by a tripped circuit at a sub-station, began in the early hours of Wednesday.
It affected all of Darwin, closing government offices and the bus network.
By mid-morning, power was back on in some suburbs and out-lying areas but thousands of residents and businesses were still waiting, local reports said.
The outage hit the whole of the city of 130,000 and extended more than 300km (185 miles) south to the town of Katherine.
The Northern Territory (NT) government is to hold an inquiry into what happened, the Australian Broadcasting Corporation reported.
"The NT public service has mobilised its emergency management protocols to ensure the community's safety," a statement on the territory government's website read.
All schools were closed, as were the courts. Motorists were being urged to use extra caution because of the traffic lights' failure, although local reports said police were manning road junctions.
"Children who are already on buses will be taken to their schools and the department of education will arrange on a case by case basis to get them home," the statement said.
"Unless advised by their department, Territory public servants are encouraged to stay at home and await further advice on power restoration."
The airport had a back-up generator and was functioning as normal, reports said, as was the local hospital.
Local officials say it will be some time before power is restored to all areas, however.
With temperatures expected to hit 33 degrees Celsius later on, according to the Australian Bureau of Meteorology, many residents look set to face a hot and sticky day.