Laws to speed up the new Women's and Children's Hospital (WCH) build on the site of the Thebarton Police Barracks have passed state parliament's upper house.
The legislation is designed to remove what the state government describes as "planning and development barriers" for the $3.2 billion project.
In September, the government scrapped existing plans to build the new WCH on a smaller, triangular parcel of land immediately west of the Royal Adelaide Hospital.
Attempts by the Greens and the opposition to amend the bill — which included a push to set up a parliamentary inquiry to investigate the project — failed to secure support.
"This is a hugely significant development, because it means that we will now be able to build a bigger, better hospital that is going to last us for future generations," Health Minister Chris Picton said.
"The previous plans were too small on a cramped site that wasn't going to be built for the future."
"To get support from a number of the cross-benchers — including SA Best and Sarah Game — we are enormously thankful for their support in backing the idea to have this bigger hospital."
As a result of the bill passing, the heritage buildings at the Thebarton Police Barracks — some of which are more than 100 years old — will be demolished.
SA Greens MLC Robert Simms said the bill had been "rushed through the parliament".
"I am concerned about the precedent that has been established here, particularly given there has not been any parliamentary inquiry to look into the legislation," he said.
"The government will have significant power over the parklands in terms of being able to accommodate police horses and stables going forward."
Mr Simms said the amendments aimed to ensure the parklands and the heritage buildings were protected.
"We want to remove the provisions of the government's bill that would allow them to annex parts of the parklands for police horses and the stables," he said.
"We also moved to ensure that the heritage buildings were going to be incorporated into any hospital development."
Opposition planning spokeswoman Michelle Lensink said the bill's passing "gives unprecedented power to the government".
"We really wanted to hold them to account [for] a range of things to do with consultation about the final approval, the relocation of the police grey horses … and the heritage elements as well," she said.
"The Women's and Children's Hospital is just being delayed because the government has gone back to the drawing board."
The government has said it would restore more than 30,000 square metres of currently blocked-off land around the hospital site to be available as accessible parklands for the community.
Its bill will now go to parliament's Lower House, where the state government has the numbers for it to pass.
The project's delivery date has been pushed out by another two years, to 2030-31.