Broken Hill mayor Tom Kennedy wants Transgrid to cover the cost of the regional town’s sudden power blackout, flagging the electricity network operator could be fined tens of millions of dollars if its emergency back-up systems are found to be flawed.

Residents in and around the NSW mining town, near the border of South Australia, are still trying to recover from a sudden storm on October 17 that brought down seven transmission towers managed by privately owned Transgrid, which hold up the single 260-kilometre power line bringing electricity to the Broken Hill region.