Households and businesses are warned to be on alert for blackouts due to shortfalls in energy supplies.
The Australian Energy Market Operator on Tuesday issued a "lack of reserve" warning for Wednesday evening, meaning the forecast demand was likely to outstrip supply in Victoria.
It said outages could be expected between 6pm and 7.30pm.
AEMO said it was seeking a market response and had not yet estimated the time it would need to intervene.
NSW and Queensland were able to avoid predicted blackouts on Monday, but were warned of possible supply shortfalls from Tuesday evening with generators revising market availability.
AEMO has also triggered the $300 megawatt hour price cap in NSW, Queensland, Victoria and South Australia as wholesale electricity prices spiked.
The operator has issued market notices to increase generation.
A perfect storm of coal-fired power station outages, high demand due to a cold snap, and problems in the global and domestic gas markets has caused the shortfalls.
The Victorian government has been contacted for comment.
