By-elections are not usually held in the Tasmanian House of Assembly because casual vacancies are filled by a recount of votes, a system that has been in place since 1917.
On 18 December 1979 the Supreme Court of Tasmania ordered that the election of three candidates in the 1979 election be declared void. The court found that Julian Amos, John Devine and John Green had exceeded their spending limits. As a result, all elected members for the electorate of Denison were required to face another election.
The election resulted in two previously elected members losing their seats: John Green from the Labor Party and Bob Baker from the Liberal Party. Elected in their place were Norm Sanders from the Democrats and Liberal Gabriel Haros.
The following candidates were elected, listed in order of election:
|Labor||Neil Batt (elected 1)||8,272||17.8||+5.2|
|Labor||John Devine (elected 5)||4,346||9.3||-2.4|
|Labor||Julian Amos (elected 4)||3,928||8.4||-3.6|
|Liberal||Max Bingham (elected 2)||5,960||12.8||-12.9|
|Liberal||Gabriel Haros (elected 3)||5,658||12.2||+7.4|
|Liberal||Robert Mather (elected 6)||2,160||4.6||+0.8|
|Democrats||Norm Sanders (elected 7)||2,798||6.0||+1.8|
|Christian Democrats||Hellen Kelly||168||0.4||+0.4|
|Christian Democrats||Stephen Shelley||167||0.4||+0.4|
|Total formal votes||46,551||94.8||-1.5|
|Party total votes|
- Newsletter of the Proportional Representation Society of Australia, Number 69, March 1993
- House of Assembly Elections, Tasmanian Parliamentary Library
- Report on Parliamentary Elections 1978 to 1980 Archived 2007-08-30 at the Wayback Machine, Parliament of Tasmania, 1980.
- A Tasmanian Political Almanac, Parliament of Tasmania
- "1980 Results in Denison for the By-Election held on 16 February 1980". Tasmanian Parliamentary Library.