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

Moorhouse had political seniority over Ward and was at the time Mayor of Wellington, but had no personal connection to Marlborough.

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

Just as Ward finished his speech, Moorhouse walked into the meeting and addressed those present for an hour, also announcing his candidacy.

[7] William Sefton Moorhouse was a senior politician who had held many important roles, but he had no connection with Marlborough.

[9] Moorhouse had twice been Superintendent of Canterbury Province and had the Lyttelton Rail Tunnel built,[8] something that he stressed to the Wairau electors, who were keen for the railway to finally reach Blenheim.

At the end of 1874, he won election as Mayor of Wellington, a role that he still held when he announced himself a candidate for the Wairau by-election.

[16][17] After further delays, Seymour finally arrived in Blenheim on 14 January 1876 to a welcome function, just two weeks prior to the election.