Powershop, which is an independent company owned by Meridian Energy, has recently added Queenstown, Wanaka and Cromwell to the area it covers.
Chief executive Ari Sargent said the company was initially focusing on the business market, but welcomed private customers as well.
Within a couple of weeks of operating in the area, 50 businesses from Queenstown and Wanaka had swapped to Powershop, he said.
"I was shocked to see how much some businesses in Queenstown are paying.
"They have really been fleeced by the power companies," he said.
Mr Sargent said he believed smaller regions such as Queenstown had less competition among power companies to push prices down than what was seen in larger centres.
"Less competition has kept the prices too high around Queenstown, but it also means the businesses here could be due for larger savings than similar companies in, for example, Auckland or Christchurch.
"The hundreds to thousands of dollars many smaller businesses are overpaying should be profit, not filling the already well-padded pockets of big power retailers."
Contact Energy, one of the region's largest suppliers, previously dismissed Powershop's claims, and Contact Energy spokesman Jonathan Hill told the Otago Daily Times "from our perspective the electricity we sell to customers is very competitively priced".
A Queenstown business which has decided to switch to Powershop is Pog Mahones Irish Pub on Rees St, owned by Frenzi Group.
Frenzi Group director Roy Thompson, of Queenstown, said the group had already moved most of its 11 businesses in Auckland and Christchurch over to Powershop, and had followed suit with Pog Mahones as soon as the option was available in Queenstown.
"You don't get different quality on power.
"So for a product like that, one might as well choose the cheapest provider," he said.
"We use a lot of power, running all our kitchen, refrigeration, lighting and audio-visual equipment.
"Each year, many of our operating costs rise relentlessly, yet we are unable to pass these on to our customers.
"Our margins are continually squeezed."
"If Powershop deliver on their estimates, then we will benefit from some very helpful savings," Mr Thompson said.
He said he expected to save about $5800 a year, the equivalent of a 20% saving, on the electricity bill for Pog Mahones Irish Pub alone, based on the estimates he was given by Powershop.
Mr Sargent said Powershop did not have a specific target for its number of customers in Central Otago, but was so far just "quietly assessing the market".
