The state government previously announced prolonged power outage payments of $1920 a week for households and $2927 a week for businesses after the storms on February 13.
Households and businesses are eligible for the payments, jointed funded by the state and federal governments, after spending a week off power.
Power distribution companies were charged with distributing the payments.
Energy Minister Lily D'Ambrosio said AusNet, the main supplier hit by the outages, had advised her on Tuesday night that its website application system was not ready despite previous assurances it would be.
She said the delay was not on.
"Here was another example where a privatised power company has failed to deliver in time for communities that are in need," Ms D'Ambrosio told reporters at state parliament on Wednesday.
"It is absolutely unacceptable."
She said she was "not polite" in urging AusNet to publish an apology to customers on its website, although one is yet to appear online.
"They are accountable as essential services to make sure their systems are ready and in place as we were assured," Ms D'Ambrosio said.
"Our inquiry will go down to the root of their systematic failure to respond in sufficient time."
The state government has commissioned an independent review into the blackout, which disconnected power to 530,000 properties across the state.
There are 1485 homes and businesses still without power as a result of last week's storms but all are expected to be reconnected by Friday.
AusNet has been contacted for comment.
13°C