The competition, which will open officially in summer, was announced by Commission for Architecture and the Built Environment chairman Stuart Lipton.
The 56 ha project is at the Chatham Maritime site, a former naval dockyard. It will include a marina, a shopping centre, a multiplex cinema, a 350-room hotel and residential development.
Chatham Maritime project director Justin Elcombe said the scheme was the largest urban regeneration project outside London.
He said: "We want this to be a flagship project that adheres to all the principles laid down by the urban taskforce.
"The development will be high-density, as well as minimise energy use such as water and cars, so it has an environmental agenda," he added.
Elcombe said the competition would include a masterplan and a detailed design for a 4 ha chunk of the scheme, including residential and mixed use.
A chair has yet to be found for the competition, although DEGW chairman Frank Duffy and London School of Economics architecture professor Richard Burdett have been advising on the project.
SEEDA is working with developer Countryside Properties and Medway council on the scheme.