Complaints to the Electricity & Gas Complaints Commission have risen by 17%.
The commision received 650 complaints In the 2009/10 financial year and handled another 1200 inquiries.
Complaints Commissioner Judi Jones says the most common complaint is about the bill people have received.
Other common grievances are with customer service, meters and debt.
Mrs Jones says the commission expects to receive more complaints in this financial year, as a result of companies being required to have the commission's details on bills.