THE Riverbank precinct will become Adelaide's new city centre, stretching from King William Rd along the Torrens to the old Adelaide Gaol site.

As the Government unveils the final designs today for the $350 million Adelaide Convention Centre expansion, above, Premier Mike Rann says he has asked the Capital City Committee to draw up options for the jail site and also the old Royal Adelaide Hospital site.

"These developments are going to change the face of Adelaide," he told The Advertiser.

"It is all about revitalising the city centre. We had a city which had turned its back on the river and now we are making the river the centre of the city.

"We need to look at what we can do and to have a new vista stretching all along the river, taking in the convention centre, the new medical centre and the new hospital until it gets to the old Adelaide Gaol site."

He said they would be the Government's next two big projects.

Mr Rann said the convention centre redevelopment meant that, along with the hospital and SA Health Medical Research Institute, the Riverbank would become the state's biggest ever building site.

The new convention centre designs have been inspired by the SA landscape, according to Deputy Premier John Rau, who was also involved in the Capital City Committee talks yesterday.

He said work would begin on the first stage of the expansion, abutting the Morphett St bridge, in September and be completed by 2014.

Stage one will have 4300sq m of multi-purpose convention space, meeting spaces and a 1000-seat ballroom built over the railway tracks up to the bridge.

Vehicles will be able to drive straight off the bridge to drop passengers at a new main entry.

The second stage, which features a distinctive hi-tech glass arrow structure capable of seating 3500 people, will be completed in June 2017.

Mr Rau said the distinctive structure was meant to evoke a cut gemstone.

He said the project, aimed at boosting the convention centre's economic and tourism contribution to SA by more than $1.9 billion over the next 25 years, would provide Adelaide with "two of its most remarkable buildings". The new buildings are a collaboration between Adelaide-based international architectural firm Woods Bagot and London-based architect Larry Oltmans from the company Vx3.

He said people would be able to walk from the Festival Centre to the Morphett St bridge on two levels - along the riverbank and a bridge-level walkway featuring cafes and restaurants.

"They (the new buildings) will re-establish Adelaide as a key national and international conference destination," Mr Rau said.

He said the buildings would allow the centre to host more and larger conferences, and "establish a stunning visual identity for Adelaide".

Mr Rau said the expansion would also act as a catalyst to attract further private investment along North Tce, including premium clothing stores, and more restaurants and accommodation.

The first stage of the redevelopment will be undertaken by a consortium including Woods Bagot, Vx3, Baulderstone, Aurecon, Bestec, Rider Levett Bucknall and Thinc Projects.

Convention centre chairwoman Jane Jeffreys said the centre had been an economic success story for SA since its establishment as Australia's first purpose-built venue in 1987.

"It will create one of the largest, most flexible and up-to-date meeting places in the world," she said.

"The development will also remove the capacity restraints, which meant we have in recent years lost hosting opportunities interstate and overseas."

Development is expected to be a key element of a headland speech Opposition Leader Isobel Redmond will make today to the Urban Development Institute.

Originally published as The new heart of Adelaide