Wellington, Aug 25 NZPA - The Electricity Commission is investigating allegations by power generators about non-payment of electricity market participants by clearing manager NZX on August 20.

Breach allegations were made by Mighty River Power, Genesis Energy and Contact Energy, while NZX had made breach allegations against Pulse Utilities in relation to the alleged non-payment, the commission said.

NZX said it reported to the commission alleged breaches by Pulse Utilities on August 20 and August 24.

Commission chairman David Caygill said the payments, due by 4.30pm on Friday were settled by 8.30am on Monday.

There was no reason at present to be concerned about the integrity of market settlement, Mr Caygill said.

The alleged breaches would be investigated to determine what actually happened, find out the cause, and take appropriate action.

Pulse chief executive Dene Biddlecombe was adamant that Pulse was not responsible for any breach on August 20.

"The allegation is that a payment was outstanding as at 4.30pm on Friday afternoon. Clearly this wasn't Pulse as we settled our trade account sometime before 3.20pm that day," he said.

"We have complied with all requirements and are not responsible for the series of events which took place between Friday afternoon and Monday morning."

It was nonsensical to suggest that a payment of just under $700,000 which was paid more than an hour before bank transactions closed for the day would affect generator payments reported to amount to $310 million, he said.

The debacle simply illustrated how urgent the need for reform of the system was, he said.

"We have consistently paid for our electricity early. The fact that Pulse Energy should be mentioned as even remotely responsible for the failure of the entire electricity payment system is typical of the bullying that Pulse Energy continually faces as a new entrant to market," he said.

Today The New Zealand Herald reported it understood a "glitch" happened on Friday after a small energy retailer failed to make a payment into the system, resulting in the NZX freezing payments to all electricity generators.