A dry winter is causing a surge in power prices for Flick Electric Co customers in the Upper North Island.
The company sent an email to customers explaining dry conditions had put pressure on the hydro lakes.
Spot prices in the North Island were up to 10.8 cents per kilowatt in June, almost double the previous year's price in the same time period.
"History tells us that dry winter conditions happen once every four or five years, and last from three to eight weeks, so we expect these conditions to be over by mid-August," the letter said.
"But this could all change suddenly if there's a decent rainfall in the right places in the South Island. There's rain forecast for later this week, so it seems the mass finger-crossing happening at Flick HQ may be working."
The letter comes after numerous complaints on the company's Facebook page.
One customer said: "Can't believe all these high prices we've had all week, so glad im [sic] leaving, just wish you'd hurry up and let me leave."
Another said "So far flick is the dearest I have every [sic] paid for my power what a rip off. Do not change to these guys."
Flick sought to assure customers they were making savings in the long run by sticking with the company.
"We're confident that most of our customers understand how our model works. We've had 102 consecutive weeks of savings, and our customers have done very well over that time. So despite some slightly higher weekly bills at the moment, they know they are much better off in the long term, and we think they'll stick around," said chief executive Steve O'Connor.
Even with higher spot prices, Flick's total price is about the same as traditional retailers', which says a lot about traditional pricing models!" O'Connor said.