"We would like to reinforce that the trust and its assets remain in a strong position, but some changes needed to be made.
"The trust have an interim manager in place, and will seek to formalise a more permanent replacement in the near future.
"Right now, we are consolidating the trust for the benefit of all of our members."
When asked what "parted ways" meant, the trust responded: "Gareth is no longer working for Te Arawa Lakes Trust" and declined to elaborate.
Attempts by the Rotorua Daily Post to contact Mr Jones for comment have been unsuccessful.
Mr Jones is still recorded as chief executive on the trust's website and a receptionist at the trust told the Rotorua Daily Post Mr Jones was on "extended leave" and did not know when he would be back.
The trust said its website was outdated in a number of areas and would be updated soon, and that "an unfortunate miscommunication" resulted in staff saying he was on extended leave.
Karen Vercoe is currently acting manager of the trust.
Established in 2006, Te Arawa Lakes Trust is responsible for the long-term management of the iwi's property, financial assets and interests, as well as the enhancement and protection of the 14 Te Arawa lakebeds in its ownership.
The trust has 20,107 registered tribal members, 17,013 of whom are 18 or over.
Those registered members are in Rotorua and across New Zealand, as well as numerous countries around the world.
The trust's interests include property investments, farming and horticulture operations, fisheries and lakes management, education services and the protection of its cultural and physical taonga.
For the financial year ending June 30, 2016, the value of Te Arawa Lakes Trust assets increased by 14 per cent to $33.7 million.