Sydney hospitals have been instructed to conserve power amid an electricity shortage.

The South Western Sydney Local Health District was told yesterday to take measures such as reducing air conditioner temperatures, halting the use of personal heaters, and avoiding the use of printers in non-clinical settings until Friday night.

See the directive below

NSW households were told to turn off non-essential appliances for several hours last night, after generators failed to come on line.

The Australian Energy Market Operator has taken control of the energy market across the east coast in a bid to secure power supply.