Labor, which had previously opposed the 23,000-seat roofed stadium at Macquarie Point, on Monday announced it would back the project.
The island state's entry into the AFL, slated for 2028, is contingent on the construction of the stadium which carries a $715 million price tag.
The project will be assessed by an independent planning commission and must pass both houses of parliament.
The Liberals, who signed the team and stadium deal, have just 14 of 35 lower-house seats in minority government and faced a tough ask to get the required numbers.
The stadium now has the backing of 10 lower-house Labor MPs.
Labor leader Dean Winter, who took over the role from anti-stadium Rebecca White after the March 23 election, said his party's changed position was about jobs.
Dean Winter says the thousands of jobs that will be created convinced him to support the stadium. (Ethan James/AAP PHOTOS)
"A stadium will mean thousands of jobs in construction, including hundreds of apprenticeships," he said.
"That's why Labor will be backing a new stadium.
"While we will not be standing in the way of the current Macquarie Point stadium proposal, we still hold concerns around the deliverability of the project."
Liberal Premier Jeremy Rockliff said it was great to see Labor get on board.
"Looking forward to working together to get this done," he said in a statement.
Labor and Liberal could hold a combined eight seats in the 15-member upper house depending on the outcome of elections in three divisions held on Saturday.
Mr Rockliff has promised to cap the state's spend on the project at $375 million and cover any cost overruns via private investment.
The federal Labor government is spending $240 million on the project, the AFL $15 million with $85 million proposed to come from borrowings against land sale or lease for commercial uses.
Mr Winter said he maintained concern about funding and believed a different "stadium 2.0" proposal should stay on the table.
It is estimated the stadium will create 4200 jobs during construction and 950 jobs per year at the venue afterwards.
Ms White had pledged to try to renegotiate the stadium deal if elected, saying it was not the right priority for the state.
The Greens remain opposed to the stadium, while a crossbench made up of three independents and three Jacqui Lambie Network members have mixed views.
Greens leader Rosalie Woodruff said it was a "stunning" backflip from Labor.
"This is a jaw dropping decision, even for the party that reversed their position on poker machines, political donation reform, mandatory minimum sentences (and) key planning laws," she said.
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