An innovative two-tower design – consisting of vertically networked platforms, terraces and verandas – has been selected winner of an AU$2bn (US$1.4bn, €1.3bn, £1.1bn) competition for a new mixed-use tower on Melbourne's Southbank in Australia.

‘Green Spine’, designed by architects UNStudio in conjunction with Cox Architects, takes the form of two curved towers that sit on top of a podium.

The taller tower, standing at 356.2m, is wholly residential but houses a public garden at its summit and will be Australia’s largest skyscraper, usurping the Gold Coast’s Q1 tower, which reaches 322.5m.

The smaller tower, reaching a height of 252.2m, will be home to a hotel and commercial space.

The podium, meanwhile, will house a marketplace, retail and entertainment spaces and a ‘BMW Experience Centre’. From the public park at the top of the podium, the spine of greenery entwines itself around the two towers right the way up.

The project is being driven by developers Beulah International.

UNStudio founder and principal Ben van Berkel said: "We are truly delighted that our design has been selected as the winning proposal for this very exciting project. For our proposal to be selected by Beulah – such a forward-focussed developer – and from entries by such an exceptional group of our peers is a true honour.

“From the outset, we worked with a fantastic team of cultural placemakers, sustainability consultants, landscape designers, artists and engineers to achieve a fully integrated design. This truly is a great result for everybody involved!"

Beulah International executive director Adelene Teh added: “The Green Spine showed work by a strong, multidisciplinary collaborative team that is a bold, yet thoroughly considered approach to creating a context-driven landmark as an addition to Melbourne's skyline.”

Other entrants to the competition included powerhouse names, such as Bjarke Ingels Group (BIG), MAD Architects, Office of Metropolitan Architecture (OMA) and MVRDV. Planning is yet to be submitted for the project.