The Bay of Plenty by-election 1957 was a by-election held in the electorate in the Bay of Plenty during the term of the 31st New Zealand Parliament on 6 April 1957.
The by-election was caused by the resignation of incumbent MP Bill Sullivan of the National Party for personal reasons on 13 February 1957.
Labour<br /> Thomas Godfrey Santon, a Taneaua dairy farmer who stood in the Bay of Plenty seat in , was selected to stand in the seat again for the Labour Party.
Liberal Federation<br /> Reginald Joseph Pedley stood for the Liberal Federation, a newly created party. The president of the Liberal Federation, James Hill-Motion, stated that the party planned to use the by-election campaign to advertise its policies to New Zealanders. He also pushed back on jibes that his party were "dissenting Social Crediters" instead saying "We are dissenting Nationalists, but we see a danger for the country in socialism." Hill-Motion had been a Social Credit candidate for in 1954, but regretted his nomination.
National<br /> There were seven names that went forward for the National Party nomination:
Butler, the chairman of the South Auckland division of the National Party, was initially seen as the likeliest candidate to win the National nomination. On 11 March a selection meeting of about 140 branch delegates in Whakatane was held and chose Allen as the party candidate for the by-election.
Social Credit<br /> The Social Credit Party decided not to contest the by-election due to the proximity to the general election, due in several months, an opinion shared by the party's Bay of Plenty branch.
The following table gives the election results:
The by-election was won by Allen who remained MP for the electorate until he retired in 1975.