Josh Willie has announced he will nominate for preselection for the Hobart-based lower house electorate of Clark.
Having sat in the Legislative Council as Labor's member for Elwick since 2016, Mr Willie will resign from parliament when the next election is called if his preselection tilt is successful.
The decision has been endorsed by Tasmanian Labor leader Rebecca White as the party readies to announce all of its election candidates next month.
Mr Willie acknowledged the move wasn't without risk for him and Labor but said it was purely about changing the government, which is formed by lower house results.
"It's not a secret that we need to build our vote in the northern suburbs of Hobart," he said.
The next Tasmanian election is scheduled to be held on or before June 28, 2025 but the island state's government has been in minority since May, when two MPs quit the Liberals to sit on the crossbench.
The resignation of former attorney-general Elise Archer in October also prompted a recount in Clark, which was won by Liberal candidate and Hobart councillor Simon Behrakis.
It returned the Liberals to holding 11 of the 25 lower-house seats.
Five Liberal lower-house MPs have resigned from Tasmanian parliament since the party was re-elected in 2021.
All were replaced in recounts by fellow Liberals.
The government, under Premier Jeremy Rockliff, has faced several no-confidence motions in parliament this year but all have failed.
Legislation was passed last year to increase the number of MPs in Tasmania's lower house from 25 to 35, restoring figures to pre-1998 levels.
Seven MPs will be elected from each of the state's five lower-house electorates.
