Lendlease and Morgan Sindall are the two firms left in the race to be named development partner on the £4bn Thamesmead Waterfront Peabody mixed-use scheme in south London.
Peabody is seeking a joint venture partner to develop 11,500 homes on the site near Woolwich, which is the largest in its 156-year history, and will make a decision this summer.
Plans for the scheme include 1m sq ft of town centre commercial and leisure space.
Peabody said it also plans to carry out comprehensive public realm improvements and community investment with the selected partner.
Located on the southern side of the Thames, the site has 2.5 km of undeveloped river front and stretches more than 100 ha east of Woolwich.
The housing association began its search for a partner for the project in April last year.
The site is set to benefit from the extension of the Docklands Light Railway across the river from Newham to Thamesmead.
The site is classed as an Opportunity Area for London, one of 38 brownfield land sites earmarked by the Greater London Authority as having significant capacity for development and improving public transport access.
Other examples of Opportunity Areas include the Old Oak area surrounding the new HS2 station in West London.
Peabody became the major landowner of the site, which spans the boroughs of Greenwich and Bexley, in 2014. The area has the ultimate potential to hold 20,000 new homes.
The association also announced a £40m investment in the area, upgrading windows in 19 towers and improving energy efficiency, on the South Thamesmead estate, famous for its use as a location in the film A Clockwork Orange.
Peabody said the land has a significant amount of green space with open grassed and wooded areas, two major lakes and an existing town centre.
Peabody executive director for Thamesmead John Lewis said: “This is another step closer to achieving our vision for Thamesmead Waterfront. Both Lendlease and Morgan Sindall have an excellent track record of developing great places at scale, and we are confident that their proposals in the next stage will reflect the unique setting of this opportunity.
“This is the largest scheme in Peabody’s long history and will form a major part of London’s growth over the next decade. With the proposed DLR extension we have the opportunity to build 11,500 new homes, thousands of new jobs and a new cultural, commercial and leisure offer for Thamesmead and for London.”