A partnership between New York architects Diller Scofidio + Renfro (The High Line, New York) and Adelaide firm Woods Bagot (SAHMRI) has won the Adelaide Contemporary Design Competition.

The international search was launched by the former Labor government as part of a plan to build a modern art gallery on the Old Royal Adelaide Hospital (ORAH) site, spearheaded by the Art Gallery of South Australia.

The winning design, which beat out five other shortlisted firms, features a performance lab, a “super lobby”, “floating” top-floor sky galleries and a suspended rooftop garden, which would display the vegetation of a pre-colonised South Australian landscape.

But the gallery is likely to look quite different under the Liberal government. Premier Steven Marshall has pledged to build a National Aboriginal Art and Culture Gallery on the site.

“We welcome the jury’s decision,” the Premier said in a written statement to Broadsheet. “Whilst the government has no obligation to build this particular design, it will certainly be considered as part of the master planning process over the coming six months. The government remains excited about a new gallery as part of the ORAH development.”

The design was selected by a nine-strong jury made up of local and international experts. Michael Lynch AO CBE, chair of the jury and special advisor to the Art Gallery of South Australia Board, said it was a “once-in-a-generation opportunity”.

“In a city famous for its festivals, the design creates a new place that embraces art in all of its forms and appeals to a broad audience, both local and international,” Lynch says in a press release.

“The jury was impressed by the winning team’s assured understanding of the future of art, performance and 21st-century programming, as well as its flair for place-making. It was an inspired insight by the winning team to conceive the building stepping down along the topography of the site and so creating a genuine connection to site and country, respectful to the Kaurna people as well as integrating the Botanic Garden into the design.”

The announcement follows reports earlier this week of plans to build Australia’s largest contemporary art gallery in Melbourne.

An exhibition of the six finalist designs, including the winning concept, is open until June 11 at the Art Gallery of South Australia.