Northern Ireland power group Viridian faces a backlash from key industrial customers, including the North's largest employer, over the price of electricity.
Bombardier Aerospace, which employs more than 7,200 people in Northern Ireland, is one of a growing number of companies which have expressed concern about the North's rising electricity costs.
It is understood the Canadian aerospace group has written to the North's Minister for Enterprise, Trade and Investment, Sir Reg Empey, to complain about energy costs and the affect that it has on the group's competitiveness.
A spokeswoman for the Department of Enterprise, Trade and Investment confirmed the minister had received a number of letters from companies on the issue of electricity costs.
The spokeswoman said a consultation paper which would examine electricity costs in the North compared to costs elsewhere in the UK and the role of the industry regulation would be issued later this year.
Mr Douglas McIldoon the electricity and gas regulator in the North said he was aware there was widespread concern about the price levels of electricity among the business community.
Mr McIldoon said: "Large users and domestic users have been ripped off during the last eight years and we do receive complaints about the current cost of electricity.
"Compared to the rest of Europe where electricity prices have been falling in some instances, the situation in Northern Ireland is unfair."
"This is now an issue for the Northern Ireland Assembly to deal with and I would hope that legislation is pending that will address the cost of electricity," he added.
He said as the industry regulator in the North his role had been limited by statute. He has called on the Assembly to bestow more powers on the office.
A spokesman for Bombardier Aerospace confirmed that the group had made representation to the Assembly to highlight what he described as the "negative" impact of the current energy price structure on its business. As one of the key employers and major investors in the North, the aerospace group has a considerable lobby in the Assembly.
The spokesman said Bombardier had publicly stated electricity costs in Northern Ireland were higher than in other parts of the UK and Ireland and this gave its competitors an advantage over the Belfast operation.
"The cost we have to pay has an impact on our competitiveness when we compete on a global market, which we do for all our contracts," he said.
Irwin's Bakery in Portadown has also voiced its concerns about the impact rising energy costs would have on its business. It considered installing its own generator but would like to see the Assembly taking decisive action on the issue of energy costs.
