New figures show small and medium sized electricity companies are chipping away at the market dominance long enjoyed by giants such as Meridian Energy and Contact.
Electricity Authority statistics show smaller companies have quadrupled their market share since 2009.
Electricity Authority chief executive Carl Hansen said the growth showed consumers were exploring their options and taking advantage of attractive deals.
"There are 34 retail electricity brands actively serving the residential electricity market and they all supply electricity that has exactly the same physical reliability," he said.
"Just because a brand has been around longer, it doesn't mean your physical electricity supply will be more reliable."
Small and medium-sized retailers were now serving over 195,000 residential customers, Mr Hansen said.
While that was still a small share of the 1.7 million home connections nationwide, it was four times higher than it was seven years ago and Mr Hansen expected it to keep growing.
The term "small and medium retailers" refers to all retailers bar the big five: Genesis, Mercury, Contact, Trustpower and Meridian.