Steve Maharey has said he will not resign, until he can avoid a by-election. What does this mean in practice. We look at S131 of the Electoral act:
Notwithstanding anything in section 129 of this Act, no writ shall be issued for a by-election to supply a vacancy in the House of Representatives if—
a) The vacancy arises in the period of 6 months ending with the date of the expiration of the Parliament and a resolution that a writ not be issued to supply the vacancy is passed by a majority of 75 percent of all the members of the House of Representatives; or
(b) Following the tabling in the House of Representatives by the Prime Minister of a document informing the House that a general election is to be held within 6 months of the occurrence of the vacancy, a resolution is passed by a majority of 75 percent of all the members of the House of Representatives to the effect that a writ is not to be issued to supply the vacancy.
Now looking at (a) the writs were returned in 2005 on Thursday 6 October 2005. That means Parliament expires on Monday 6 October 2008. Six months prior to that is Sunday 6 April 2008. So Maharey can resign anytime from 6 April onwards and avoid a by-election.
He can resign safely before that date, but that will then require the PM to name the election date, or at least the latest date she will hold the election. For example if he resigned on Thursday 20 March 2008, then Clark could table a document saying the latest date for an election would be Saturday 20 September 2008. This last happened in 1996 when did such a declaration to avoid a by-election in Hawke's Bay following the resignation of michael laws.