A Development Securities spokesperson confirmed it was in talks, although she declined to name the contractor.
The developer received funding for the first 2500 m2 phase in August from insurance group Standard Life. The phase received detailed planning consent last November.
The scheme is to be designed by Aukett Europe and the project team also includes M&E engineer FaberMaunsell, QS AYH and structural and civil engineer Pell Frischmann.
Development Securities was first appointed to redevelop the 20 ha site by the London Development Agency in February last year.
The project is a key part of the Thames Gateway regeneration plan, which deputy prime minister John Prescott sees as a key element in the government's housing strategy. He has earmarked 200,000 houses for the area, to be built over the next 20 years. The area could also host a Crossrail station.