One of the nation's biggest energy projects has been given the green light, with a Liberal premier fighting to form government staking his leadership on the deal.
The multi-billion-dollar Marinus Link cable will boost electricity transmission between Tasmania and Victoria and is seen as pivotal in increasing green energy investment.
Tasmanian Premier Jeremy Rockliff signed up to the joint Victoria and Commonwealth investment contract on Friday, while in caretaker mode and a day before the deadline.
Mr Rockliff has been lashed by Labor, the Greens, as well as several independent crossbenchers whose support he needs to form government, over a "sham" process.
He says Marinus Link will deliver 2000 jobs and $400 million per year in extra revenue to Tasmania and that power prices will be lower than without the cable.
Craig Garland, one of four independents on the cross bench, has said he won't be able to support a Liberal government over their "secret" rushed decision.
It leaves the Liberals, who have 14 seats ahead of Labor's 10, with one less cross bench option to sure-up the required 18 parliamentary votes needed to govern.
Non-Liberal MPs were given a confidential briefing on the project on Tuesday, while the whole-of-state business case wasn't released before the deal was signed.
"If I fall because of this project ... I will know in my heart of hearts I have done the right thing by Tasmania and Tasmanians," Mr Rockliff told reporters.
"This is not about me, this is not about Craig (Garland). This is about the young people in Tasmania and their kids and their grandkids.
"Staking my leadership is what I do."
Independents Kristie Johnston and Peter George were also critical of the process, with the latter saying Mr Rockliff was undermining the prospect of a full-term, well-run minority government.
Mr Rockliff said the "deal of the century" had capped Tasmania's equity share at $103.5 million - 4.27 per cent of the project's cost.
However, the business case forecasts an increase in state net debt to $19 billion in 2031/32 as a result of the project, which includes a power station redevelopment and land-based transmission line.
Tasmania's major industrial customers also face "very large" increases in transmission prices, compared to a no-Marinus-Link scenario.
Construction of stage one, a 750-megawatt undersea cable, is expected to start in 2026 and finish in 2030.
Federal Energy Minister Chris Bowen said the project was a cornerstone of his government's commitment to reducing emissions and creating jobs in regional communities.
Supporters of Marinus Link are confident the cable will lead to greater green energy investment in Tasmania, which can be exported into the national grid.
Labor leader Dean Winter supports Marinus Link, but earlier this week said he was unable to back the deal on such short notice.
He has given Mr Rockliff "first crack" at forming government but has also reached out to the cross bench, who he is prepared to work with to avoid going back to the polls.
Tasmania's snap election on July 19, the second in two years, was called after Mr Rockliff lost a no-confidence motion critical of his budget management and infrastructure delivery.
