Federal energy minister Chris Bowen has put energy retailers on notice for failing to pass on electricity price reductions, amid reports that consumers across the NEM are facing bill hikes just weeks after regulators confirmed that the cost of power is set to fall across the board.

In a letter to the Australian Energy Regulator (AER) and the Australian Competition and Consumer Commission (ACCC), Bowen asks the two watchdogs to look at the way retailers are packaging up costs to households and businesses, and to make sure they are not flouting the rules.

Of particular concern is the trend towards jacking up the fixed-cost component of the bill stack – the fixed daily charge for connecting to the grid – to the extent that it cancels out any savings from falling wholesale power costs, and often results in a higher overall bill.

This practice has come into stark relief in the wake of final determinations from the AER and the Victorian pricing regulator last month that promised power prices would fall for the majority of households and all small businesses across National Electricity Market (NEM) states.

“The Default Market Offer is very clear,” Bowen told a press conference on Wednesday. “There are reductions, small in some cases and quite substantial in others, across the board. There is a very small increase in South Australia and reductions everywhere else.