Capital Shopping Centres said the plans were backed by 88 per cent of people who attended a public exhibition during public consultation.
Construction could start in 2013 if the plans are approved by the Thurrock Thames Gateway Development Corporation, with the extension likely to open in 2016.
Planned transport improvements include a bus station linked to Chafford Hundred rail station.
Retailers Arcadia and Forever 21 recently signed deals to open stores at the shopping centre.
Jonathan Ainsley, director of asset management in the south at CSC, said: "Lakeside, which celebrated its 21st anniversary this year, continues to be high on retailers’ wish lists as evidenced by the recent Arcadia and Forever 21 deals and the planned extension enables us to accommodate bigger and better stores for many more retailers too."