The South Australian government has inked a deal with private developer Walker Corporation for the major upgrade.

It will include an office building, two levels of restaurants, cafes and bars, an underground car park and public artwork.  Walker Corporation will commit $430 million, with taxpayers chipping in $180 million.

Premier Jay Weatherill says the plans represent a “great deal” for the state.

“We’re using $180 million to leverage about $1 billion when you add in the casino’s $360 million redevelopment,” he told ABC radio on Monday.

“There couldn’t be a more important part of South Australia in terms of its cultural activities.”

The revamp of the site, adjacent to Adelaide Oval, includes an upgraded Festival Centre theatre.  Construction is scheduled to begin at the end of the year and finish within three years.

Greens MLC Mark Parnell questioned whether the deal provided good value for taxpayers.

“What we don’t know is whether the state contribution is about the right amount for the public component of these works,” he said.

Adelaide's Festival 1