Assuming the New Zealand Maori Council is unsuccessful in its challenge to the planned sales in a Supreme Court hearing later this month, the government's intention is to sell up to 49 per cent of MRP, while maintaining a controlling 51 per cent stake in taxpayers' hands before June 30.
The price cut comes after a year in which electricity prices rose by an average of 5.2 per cent across the country, against the tide of total inflation for the year of 0.9 per cent, according to Statistics New Zealand's consumers price index for the December 2012 quarter, released last week.
The value of the reduction per household on average is some $2.50 a month, Mercury said in a statement.
Mercury general manager James Munro said the impact of distribution and transmission charges accounted for more than 40 per cent of the monthly power bill, the majority of which is the local distribution charge.
"Combined with an increase in the transmission charges from Transpower (the national grid operator), which are also regulated under the Commerce Act, total lines charges are decreasing by an average 7.5 per cent," Munro said.
"Within the overall review of our prices, Mercury Energy has increased its energy charge by 2.9 per cent to meet general cost pressures within our retail business," he said. "The energy charge accounts for just under 60 per cent of the total bill."
Prices for other regions will be available in coming weeks once all distribution company and Transpower charges are known.