Municipalities in Gauteng province run by the ruling African National Congress still owe power utility Eskom billions of rand in unpaid bills for electricity, the main opposition Democratic Alliance (DA) said on Thursday, citing a consolidated first quarter report.

It singled out Emfuleni, Merafong and Rand West City among the worst offenders.

"The total debt these municipalities owe to Eskom is R1.5-billion, of which R1.1-billion is owing for more than one month from due date," DA Gauteng spokesperson on finance Ashor Sarupen said.

Sarupen said Emfuleni's debt to Eskom was at R911-million while Merafong owed R81-million and Rand West City R165-million.

"At a time of rolling blackouts and load-shedding, outstanding municipal debt to Eskom should be settled to shore up its balance sheet and ensure that our energy grid is not compromised," he said.

On Thursday the cash-strapped state company said it would continue with the rolling powercuts it has been forced to implement countrywide for more than a week to avoid a total collapse of the grid under demand pressure.