The dividend policy change was announced in the company's latest Statement of Corporate Intent for the years 2013 to 2015 and will apply to after-tax profit, adjusted for the impact of changes in the fair value in financial instruments and any accounting impairments.
Non-cash impacts of changes in the value of financial instruments typically creates volatility in reported earnings which does not reflect underlying performance.
The 75 per cent dividend payout ratio had been in place since 2010 while MRP committed more than $1 billion in capital to a series of geothermal developments in New Zealand and offshore over the past five years.
However, demand for electricity has been static for the past three years, with no significant load growth forecast in the immediate future.
"MRP is now adjusting to the current outlook for New Zealand electricity supply and demand with less operating cash flow now allocated to new domestic projects and higher dividend flows to owners," said chairwoman Joan Withers.
By comparison, NZX-listed Contact Energy - formerly state-owned - targets an 80 per cent payout ratio "over time", according to the company website, although chairman Grant King indicated at this year's annual meeting that higher capital returns to shareholders were also on the cards because it had few capital needs in the immediate future.
MRP's Withers said: "The board has gained confidence to increase the dividend pay-out ratio due to the successful execution of our geothermal strategy.
"In October we saw the first cash returns from our international investment through the GeoGlobal Energy (GGE) Fund and our Ngatamariki Power Station, near Taupo, is due for completion in mid-2013."
Dividends would be subject to working capital requirements, the medium term asset investment programme and a sustainable financial structure for the group.