Dramatic plunges in spot power prices to levels as low as negative $1000 a megawatt- hour this week underline the critical need for an overhaul of the National Electricity Market to help avoid blackouts as coal power plants shut down, according to the country's top energy market overseer.

"I don't think anyone any more is suggesting the status quo is acceptable," said Audrey Zibelman, chief executive of the Australian Energy Market Operator, pointing to broad agreement from federal and state energy ministers on the need for market reform as Australia transitions towards clean energy at world-leading pace.