A long-term agreement has been signed between Tuwharetoa Maori Trust Board and Mighty River Power for the storage of water in Lake Taupo.
Lake Taupo is the primary source of Mighty River Power's Waikato hydro storage for its hydro scheme, which accounts for around 10 per cent of New Zealand's total electricity supply.
The hydro storage also benefits downstream users of water, including Hamilton and Auckland drinking water supplies.
Mighty River Power chief executive Fraser Whineray said the agreement reflected the strong working relationship the company enjoyed with Tuwharetoa.
"The Waikato is New Zealand's most important water catchment, providing tremendous economic and societal benefits, which we can grow for this country. Through this agreement we have both committed to working together into the future, and we look forward to those opportunities."