Attorney-General Elise Archer resigned on Friday afternoon, taking a swipe at party leadership for failing to support aspirational women.
It was revealed on Thursday Ms Archer, elected to parliament in 2010, was being investigated for reported bullying allegations made against her by staff from her office.
The Australian newspaper published alleged text messages from Ms Archer in which she labelled Premier Jeremy Rockliff "gutless" and his predecessor Peter Gutwein as having a "glass jaw".
Ms Archer's departure leaves the only Liberal government in Australia with 10 of 25 lower house seats in Tasmania.
The government has been in minority since May, when two MPs quit to the crossbench citing concerns with Tasmania's deal for an AFL team and stadium.
Mr Rockliff did not rule out delaying the return of parliament, scheduled to next sit on October 17, to ensure a recount could be held to determine Ms Archer's replacement.
The government has survived no-confidence motions in parliament in recent months but is at greater risk of losing a vote if it faces parliament with just 10 members.
"I'll be seeking advice in respect to the timeline of an election of a new member of parliament and will make my decision accordingly," Mr Rockliff told reporters.
Mr Rockliff said the alleged text messages had nothing to do with his decision to ask Ms Archer to resign from cabinet.
He said he received additional information about comments she made, beyond what was reported in the media.
Ms Archer's replacement in the Hobart-based seat of Clark is expected to be a Liberal.
Several Liberal MPs, including Mr Gutwein, have quit since the party's re-election in 2021.
Mr Archer's resignation comes as the government grapples with the public release of a report into child sexual abuse that found grave failures in state institutions across decades.
She was the state's first female Speaker and became attorney-general in 2018.
"It is clear to me that the leadership of the Liberal Party continues to fail to support ambitious women," she said in a statement.
Deputy Premier Michael Ferguson is acting attorney-general, with Ms Archer's portfolios to be assigned in coming days.
Mr Rockliff shuffled his ministry in July after dropping the health portfolio as part of a "reset".
