More than a million households and businesses are set to benefit from the extension of electricity price protections.
The Morrison government's default market offer will be offered to households and businesses with solar systems and with flexible or time-of-use tariffs in NSW, South Australia and southeast Queensland from July 1.
The existing offer only covered residential and small business customers who were on flat tariffs or had controlled loads.
The default market offer is a price cap that protects loyal customers from excessively high standing-offer contracts.
It sets a maximum price a retailer can charge electricity customers on standing offers, and acts as a reference price that energy retailers must use when advertising or promoting offers, making it easier to compare offers.
Energy Minister Angus Taylor said it would particularly help those who found pricing and discounts confusing, or did not have time to negotiate a better deal.