CEO of the convention centre Rashid Toefy said the project, "which will change the face of Cape Town", would cost R690-million over the next three years.
The bulk of the funding will be provided by the city, which owns 51% of the shares in the convention centre, assisted by the Western Cape provincial government, which has a 25% stake.
Piet Bakker, of Stauch Vorster Architects, Anya van der Merwe, of Van der Merwe Miszewiski Architects, and Mokena Makeka, of Makeka Design Lab, were awarded the contract yesterday.
Toefy said the exciting expansion, and the calibre of the architects appointed to lead it, were essential to achieving the centre's goal of becoming the best long-haul international convention centre by 2020.
He said the expansion, which will comprise 10000m2 of retail space, a hospital and an office tower, would boost the Foreshore precinct's redevelopment.
The ANC recently reported alleged irregularities in the acquisition of the prime property, from media company Naspers, to the public protector.
Toefy said: "We absolutely welcome the public protector looking into it. If she investigates she will realise it's a commercial deal and that what the city is paying Naspers is what the land is worth."
The Competition Commission was also scrutinising the sale to ensure there was no "other hindrance", he said.
The land is currently being used as a parking lot. The commission is investigating because the city, a shareholder in the convention centre, also owns parking space.
Makeka said the expansion project would boost the city's stature as 2014 World Design Capital.
The International Council of Societies of Industrial Design awards the title every two years to promote cities that use design for social, economic and cultural change. Cape Town is the first African recipient of the title.
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