There are fears that more gas price rises could be in the offing.
Mercury Energy last week raised the retail price of natural gas to its 39,000 customers by an average of 10%.
The company blamed higher costs of moving gas through pipelines and dearer prices for wholesale gas.
The Domestic Energy Users Network fears this could be just the start. It quotes from a range of scenarios saying gas prices could double in five - 10 years and could redouble in another five years.
The wholesale price of gas has already doubled since the heyday of the Maui field.