The by-election was caused by the resignation of incumbent MP William Henry Eyes and was won by Arthur Seymour, who defeated Joseph Ward.

[4][5] In December 1871, Eyes was appointed Crown Lands Commissioner for the Marlborough Province and as a public servant, he could no longer hold a seat in parliament or the provincial council and had to resign.

Arthur Seymour was another prominent politician in the Marlborough Province, and a strong rival of Eyes.

Seymour was Superintendent of Marlborough in 1864 and 1865, and when he was succeeded by Eyes, the capital seat was moved to Blenheim.

[8] Like Seymour, standing in the Wairau by-election was Ward's first attempt of getting elected to the general assembly.

[10] The results by polling booth were as follows:[10] Seymour remained a member of the General Assembly until his resignation in 1875 prior to a trip to England.