Te Arawa Lakes Trust has appointed interim manager Karen Vercoe as its new chief executive after an extensive six month review of its activities, financial processes and operating structures.
The trust announced its chief executive Gareth Jones had "parted ways" with the trust in February.
Mr Jones was also chief executive of the trust's management subsidiary - Te Arawa Management Ltd.
He served just over 12 months with the trust after being appointed in late 2015.
Ms Vercoe - Ngati Pikiao and Ngati Makino - has extensive governance, organisational development and management experience across industry sectors, including working with iwi, Maori and Pacific service providers, Whanau Ora collectives and other not-for-profit organisations.
In 2016 she received the Dame Mira Szasy Maori Alumni Award at the Maori Business Leader Awards. She also received the University of Auckland's Kelly Research Scholarship in 2006.
She is chairwoman of Te Pumautanga o Te Arawa and is a former New Zealand double international representative in rugby and touch rugby.
Ms Vercoe has been acting as the trust's interim general manager since the departure of Mr Jones in December last year.
Trust chairman Sir Toby Curtis said the trust had spent six months undertaking an extensive review of its previous 12 months of operations.
He said while the review highlighted some areas for improvement, it also accentuated some significant areas of opportunity in terms of its future structure and operations.
"Our review was wide and all-encompassing and as a result of this process it has become crystal clear that we need to focus on our core purpose and stick to what we do well - managing our assets responsibly and sustainably."
Sir Toby said the responsibility incorporated the trust's physical and financial assets, as well as its environmental assets, such as the protection and enhancement of Te Arawa lakes.
"We cannot afford to become distracted by non-essential interests that are outside our core mandate.
"Now is the time to refine our focus on our core business and to implement the most effective and efficient operating framework for the current and future needs of our people."
He said the trust would now outsource its administrative and financial functions, bringing in specialists to help with its environmental and project work, and looking for alternative providers to take on its employment and training students.
Sir Toby said the training unit had been an important social endeavour, but was an example of an interest that was outside its core purpose.
"The unit's operation has become more challenging in recent years due to a number of changes in the funding environment, which has placed considerable strain on the trust."
He said the training unit would be closed down "and we know that its services can be more effectively delivered by other organisations who are better equipped to satisfy the funder's requirements and those of the students".
The trust's environmental manager, Roku Mihinui, will also be moving on to embark on a career as a consultant in the environmental, social and cultural arenas.
Sir Toby said Mr Mihinui had made a significant contribution to the trust, the Te Arawa people and the lakes environment over the past 15 years.
"This is an exciting new phase of Roku's professional career and we hope he may choose to work with us on specific projects within our environmental portfolio in the future.
"We wish Roku all the best in his new endeavours."
The trust has 20,107 registered tribal members, 17,013 of whom are aged 18 and over.