Australia's only state Liberal government was thrust into minority status on Friday after two MPs quit, citing concerns over state debt and government transparency around the planned build on the edge of the Hobart CBD.
Those issues were echoed at a rally outside state parliament on Saturday as thousands rallied with signs including, "Team yes, Stadium No. Tell the AFL where to go!" and "We can't eat stadiums or submarines".
"You can stick your stadium up your bum," musicians sang to applause.
Senator Jacqui Lambie soon joined in, telling Premier Jeremy Rockliff "Tasmanians have had a bloody gutful over your stadium and you can stick it up your bum."
Federal independent MP Andrew Wilkie addressed the rally, having earlier told parliament the 23,000-seat arena would look "at best like a monument to stupidity, at worst like a giant bedpan".
Tasmania's Labor opposition meanwhile took issue with the AFL making the stadium a condition of Tasmania getting a team licence to join the league.
The state will enter the men's league in 2028 with a pathway into the women's league to be announced.
"We all know a Tassie team is richly deserved and should've been granted with no stadium attached," Opposition Leader Rebecca White said in a statement.
"But what should've been a unifying moment for Tasmania has been ruined by Jeremy Rockliff's reckless decision to write a blank cheque for a stadium we don't need."
The onus was now on Mr Rockliff to earn back Tasmanians' trust by committing to full transparency on the AFL stadium deal, state independent MP Meg Webb said.
"They arrogantly dismissed the concerns, questions and warnings raised by many Tasmanians from all walks of life over this issue," she said.
The loss of the two MPs leaves the Tasmanian Liberals with 11 out of 25 seats in the House of Assembly. They will need the support of two of the six crossbenchers to pass legislation.
"I'm extremely disappointed, but I'm getting on with the job," the premier told reporters on Friday.
"People might not always agree with what we are doing, but we are doing it for the right reasons."
Defending the stadium, Prime Minister Anthony Albanese said plans to upgrade the Macquarie Point site went back to at least 2012 when he was infrastructure minister under Julia Gillard.
"This site has been left derelict for too long."