Every House of Representatives shall continue for three years from its first meeting. As the current House first met on 12 February 2008 it is due to expire on 11 February 2011, although it may be dissolved sooner with the election date nominated by the Prime Minister.
If the House of Representatives continues until its expiry date, then the election must be held on a Saturday no more than 68 days later, that is by 16 April 2011.
Although the election of senators whose terms expire on 30 June 2011 may be held as late as 21 May 2011, a simultaneous House of Representatives and half-Senate election must be held no earlier than 7 August 2010 and no later than 16 April 2011.
A double dissolution election cannot be held later than 16 October 2010.
For details, see R Lundie, Australian elections timetable, DPS Background Note, 2008-09 at: www.aph.gov.au/library/pubs/bn/2008-09/Aust_elections.htm