The Government's mantra that a competitive electricity industry will drive down power bills is false, Labour is claiming ahead of a visit to Parliament by energy executives.
The Electricity Authority and Genesis Energy will appear before a select committee tomorrow morning for their 2012/13 financial review.
Labour energy spokesman David Shearer said he would challenge the authority on its belief that a highly competitive market was leading to lower power prices.
"My belief is that competition hasn't been as effective as Government and the power companies are claiming.
"The bottom line is that consumers are continuing to face increasing prices and there is nothing that I can see that will be able to bring those prices down as the market is currently structured."
Labour and Greens are promising to introduce a single electricity buyer if elected, but Government believed this model would stifle competition and lead to higher electricity bills.
The Electricity Authority said last week that strong competition in the electricity market was forcing retailers to absorb cost increases rather than pass them on to customers.
It said that costs incurred by retailers had increased by 21.5 per cent over the last three years but prices charged to consumers over the same period went up by just 12.5 per cent.