The Maori King, Tuheitia, is attending the initialling of a Waikato tribe's Treaty settlement package at midday on Friday.
Colonial troops confiscated Ngati Haua's tribal lands after an invasion in 1863.
The Crown will apologise to Ngati Haua for the attack and other breaches of Tiriti o Waitangi.
The Office of Treaty Settlements is planning to transfer a number of Crown properties to the iwi, including the Morrinsville courthouse - which would then be leased back to the state.
The King's flag has been raised at the ceremony at Te Iti O Haua Marae in Hamilton.