The regulator of the wholesale electricity market says a price spike on March 26 was an undesirable trading situation and it will reset offer prices for that day.

The Electricity Authority's estimates suggest the new offer prices should be set between $1500 and $3000 per megawatt hour (MWh). Spot prices north of Hamilton rose to more than $20,000 per MWh for several hours on March 26.

The authority started a market performance investigation and ordered a delay of final prices for that day, while 35 claims of an undesirable trading situation were investigated.