The name Ōnuku translates to 'food for a journey', 'never staying long' or 'coming and going', as a reference to the kāinga's location as a stopping point on the way to larger settlements in the Akaroa harbour.

[8][9] After the massacre at Takapūneke in 1830, in which attackers from the North Island led by Te Rauparaha destroyed the kāinga, survivors relocated to Ōnuku.

[9] When French doctor Louis Thiercelin visited Ōnuku in 1840 the kāinga consisted of around 30 small huts, with the chief living in a larger three-room whare (house) closer to the water.

[6] European settlement grew the town to a population of around 150 at its peak, but it primarily remained a major centre of cultural life for local Māori during the late–nineteenth and twentieth centuries.

[11][12] The treaty was brought south from the North Island to Akaroa on the HMS Herald by Major Thomas Bunbury, with Edward Marsh Williams serving as interpreter.

Iwikau was a rangatira (senior leader) of the Ngāti Rangiāmoa hapū of Koukourarata (Port Levy), and half-brother of Ngāi Tahu ariki (paramount chief) Te Maiharanui.

The church was restored and traditional carved panels were added to the porch in 1939 for a centenary of Akaroa service in 1940, an event attended by over 1000.

[2][17] In 1976 a new fence was built, and a poupou Tumiki, carved by Pere Tainui and gifted by Te Wai Pounamu Old Girls Association, was erected beside the church.

[8] The whare kai (dining hall) opened in 1990, and was named Amīria Puhirere after a local female leader who had lived to over 100 years old.

[13][8] In 2019, the Governor-General of New Zealand Dame Patsy Reddy attended Waitangi Day commemorations hosted at Ōnuku.