According to data from the Electricity Authority, if every New Zealander switched power companies within the last year, a combined total of $307 million could of been saved.
In the year to December 2015, 12 of New Zealand's 16 regions had an increase in the number of electricity retail brands available for consumers to choose from.
Consumers switched among them in record numbers – almost 418,000 consumers changed their electricity supplier during the year.
The Electricity Authority said the average amount they could save was $175 a year.
Carl Hansen, Electricity Authority chief executive, said the market was becoming increasingly competitive, as consumers started to take more notice of what was available to them.
The report showed growth in small, independent brands. Together, these brands now have almost 80,000 customers, up 12 per cent compared to the year before.
"While many of these retailers remain small, they are adding competitive pressure from the margins, which means the larger players need to keep innovating in order to maintain their market share," Hansen said.
"As well as more choice in the number of retailers available, a big trend in 2015 was more innovative electricity plans and payment options on offer," he said.
The number of pre-pay electricity contracts has increased substantially. At the end of 2015 there 43,560 pre-pay accounts, compared with 30,804 pre-pay accounts at the end of 2014. There is also a trend for contracts that have different pricing at different times of the day—119,953 consumers are now on this type of contract."
The Authority's review lists a range of other new options that are now available to electricity consumers including one retailer offering a "free hour of power", one retailer bundling electricity with gas, telecommunications and pay TV, other retailers passing on spot electricity prices and a range of new consumer apps and web tools available to help customers manage their bills or monitor their usage online.
Some retailers are now offering electricity plans targeted to electric vehicles or solar schemes.
Hansen said consumers should regularly check they were getting the best deal they could.