Victoria, South Australia, Tasmania and southern NSW have all sweltered through the second day of what is forecast to be the worst heatwave of the year, throwing festivals and major events into chaos and putting the power grid operator on alert.

The organisers of one of Victoria’s largest music festivals, Pitch Music and Arts festival in Moyston – 220 kilometres north-west of Melbourne – pulled the pin late on Sunday, after outraged parents were left fuming as organisers forged ahead with more than 15,000 attendees, despite extreme heat and fire warnings.