Susan Edmunds, Money Correspondent

High wholesale power prices are already reducing the deals that households can get on their electricity, a price comparison website says.

Powerswitch said it had been advised both Comtricity and Raw Energy had stopped trading.

In addition, it had been asked to remove offers from Octopus, Nova, Electric Kiwi and Flick Electric from the site.

Independent retailers had been under pressure in recent months as wholesale power prices soared.

In July, Electric Kiwi said it had to close to new customers because it could not afford to take them on.

On 20 August last year, wholesale prices were as low as $77.53/MWh - on Monday they were more than $300.

"These retailers' offers are temporarily not shown on the Powerswitch results page, while they are not seeking to take on new customers due to adverse market conditions," Powerswitch general manager Paul Fuge said.

"Hopefully, they will be back soon. But we fear if the situation continues it may be some retailers elect to shut up shop completely, which would be detrimental to retail competition.

"I'm not sure how long retailers will be able to hold out for if wholesale prices continue to be elevated. The pressure will surely be on to increase retail prices at some point in the near future."

Octopus Energy chief operating officer Margaret Cooney said it had withdrawn from Powerswitch because of problems accessing hedge contracts.

She said customers were experiencing significant price increases - compared to July, the best offer for a Christchurch household on Powerswitch was $700 a year more with Meridian and $900 with Mercury.

A Meridian spokesperson said that deal was a special rate with Orion offered for just over a month. "The special rate has come to an end."

Fuge said Powerswitch had been close to listing 2Degrees because it offers electricity on some of its plans.

"The current conditions will likely delay this."

He said Powerswitch would watch gentailers' profit levels with interest.

On Monday, Contact Energy reported revenue growth of 35 percent and a net profit of $235 million.

The Energy Collective chief financial officer Nick Haines said he had seen data that indicated some of the offers withdrawn from Powerswitch, including deals from the major power companies, had been "leading and essentially keeping prices down for consumers".

"The fact that across a number of main regions you've had offers from gentailers that have been withdrawn in the last few weeks, indicates we are likely to see prices increase."

It seemed obvious if there was less competition, it was more likely that prices would rise, he said.

Electricity Retailers Association chief executive Bridget Abernethy said wholesale prices were high and could be volatile, but most consumers were not exposed to spot-price movements.

The issue had been caused by fuel supplies and a dry year, she said.

"The thing we really need to do more than anything is invest in more supply to bring those prices down."

Abernethy said investment in renewable generation had doubled in the last 18 months.

Deals with Methanex and the aluminium smelter at Tiwai had generated extra capacity to help with the current squeeze.

Things were tough for households and businesses after years of increasing costs but electricity prices had been relatively flat, Abernethy said.

MBIE data showed the average residential power bill this year, including GST, was $2343, compared to $2316 last year; in 2022, however, it was $2460 in real terms.

This story was first published by RNZ