The Wairau Affray (called the Wairau Massacre in many older texts), on June 17, 1843, is the first serious clash of arms between Māori and the British settlers in New Zealand after the signing of the Treaty of Waitangi and the only one to take place in the South Island.

The incident is sparked when a magistrate and a representative of the New Zealand Company, who hold a possibly fraudulent deed to land in the Wairau Valley in the north of the South Island, lead a group of European settlers to attempt to clear Māori off the land and arrest Ngāti Toa chiefs Te Rauparaha and Te Rangihaeata.

Fighting breaks out and twenty-two British settlers are killed, several after their surrender.

Four Māori are killed, including the wife of Te Rangihaeata and the wife of Te Rauparaha.

The incident heightens sfears among settlers of an armed Māori insurrection.

It creates the first major challenge for Governor Robert FitzRoy, who takes up his posting in New Zealand six months later.

FitzRoy investigates the incident and exonerates Te Rauparaha and Te Rangihaeata, for which he is strongly criticized by settlers and the New Zealand Company.

In 1844 a land claims commission investigation determinez that the Wairau Valley had not been legally sold.

The government is to pay compensation to the Rangitane iwi, determined to be the original owners.