In 1996 the general election date was brought forward slightly, to 12 October, to avoid a by-election after the resignation of Michael Laws.
In the past it was not uncommon for an MP who died in office to be replaced with an immediate family member such as a brother, wife (see widow's succession), or son.
This practice has however fallen out of favour since the mid-seventies with the election of John Kirk to his late father's seat being the last occasion this happened at a by-election.
[2] Twelve Prime Ministers first came to parliament via by-elections: Julius Vogel, Harry Atkinson, Robert Stout, John Ballance, William Hall-Jones, William Massey, Peter Fraser, Keith Holyoake, Walter Nash, Bill Rowling, David Lange and Geoffrey Palmer.
The 1926 Eden by-election was won by Labour who became the official opposition, helped by a split over the Reform candidate selection.