Up to 100,000 Victorian premises could be without power during this week's heatwave as demand cripples the state's electricity grid.
It follows reports of power failures since Monday, with power companies reporting problems on their networks, which are struggling to cope with demand from Victorians attempting to cool down.
The Australian Energy Market Operator informed the Victorian Government on Wednesday afternoon that it could be forced to cut some supply to the state despite temperatures expected to reach 44 degrees on Thursday.
Energy Minister Nicholas Kotsiras said demand from interstate and reduced capacity from Loy Yang A power station in the Latrobe Valley was placing an additional strain on the state's electricity network.
He said any power failures would not affect hospitals, nursing homes, public transport or emergency services.
Non-critical maintenance has been cancelled and large energy users have agreed to reduce their use.
Thousands of homes across Melbourne, including in Maidstone, Glenroy and Williamstown already lost power for hours at a time since Monday. Deakin University's Burwood campus was forced to close on Wednesday afternoon due to unexpected power failures.
Powercor reported 15,685 premises without power across the western suburbs and United Energy reported about 3500 on the Mornington Peninsula lost power during the heatwave.
SP AusNet stated that electricians were working to restore power as quickly as possible.
Premier Denis Napthine urged people to only use "essential" electrical devices, especially during peak demand periods.
He told radio station 3AW: "We're urging Victorians to help out with the power supplies, with the high heat and the high demand for electricity ... we've had a warning from the Australian Energy Market Operator that there might need to be a reduction in supply in certain areas," he said.
The peak use period is between 2pm and 6pm. Wednesday's maximum temperature is 41.7 degrees.
With Stephen Cauchi