Power customers are switching companies at the highest rate for more than two years.
Across all retailers in November, some 37,000 customers changed electricity company, according to a monthly report from Meridian Energy.
The 12-month average switching rate was 19.6 per cent at the end of November, the highest since the middle of last year.
A recent global report on household electricity prices showed New Zealand had the highest level of retail "churn" in the world, ahead of Belgium and Australia which are just under 18 per cent a year.
The VaasaETT report said New Zealand had some of the most efficient switching procedures anywhere, with "a good supply of competitors".
The latest government survey of household prices estimates the average tariff as 28.5 cents a kilowatt hour, which would make prices about the fourth cheapest compared with European countries.
For Meridian alone, customer numbers were down more than 8300 in the past year, to a total of 276,403.
At the end of last year, Meridian's customer connection numbers dropped about 14,000 after Energy Direct's decision to operate as an independent retailer. Earlier this year, Trustpower bought Energy Direct, which had electricity and gas customers in the Whanganui region.
However, since the middle of this year Meridian customer numbers have improved 1.6 per cent, with more North Island customers.
Meanwhile, Meridian's instalment receipts were back to $1 each yesterday, their original selling price in the government's share float earlier in the year. The shares fell as low as 89.5c earlier this month.
A Morningstar report out yesterday gave a fair value estimate of $1.16 for Meridian's instalment receipts, based on an estimated fair value of $1.75 for the full shares.
Meridian has a strong competitive position. Meridian and other incumbent power companies would generate solid returns above the cost of capital in the long term.
But from time to time, Meridian would be hit by poor hydro lake levels in drought or poor snowmelt. That meant Meridian's earnings would be more volatile than its peers.
As well, the regulatory risk of Labour changing the electricity system through a single buyer could cut Meridian's operating income by $170m a year. That meant there was a high uncertainty to the estimated fair value.
In the year to date, Meridian's inflows and storage in its South Island lakes remained high compared with historic averages.
Meridian's generation was 11 per cent higher than last year in the financial year to date, between July and November.
Its market share increased in November, with its weekly share above 40 per cent by the end of the month.
But the average price Meridian received for its generation in November was 12 per cent down on the same month last year, reflecting the higher than average hydro power storage.
Meanwhile, national demand remained subdued, Meridian said, with the long-term decline in industrial demand for power. Demand this year remained flat compared with last year because of lower demand from the Norske Skog Tasman Mill and a mild winter reducing household demand.
But South Island demand in November was up 10 per cent on the same month last year, with higher irrigation load in Otago and Canterbury.
The Tiwai Point smelter's average load in November was slightly above the 572 megawatt base quantity agreed with New Zealand Aluminium Smelters.