Assembly members Darren Johnson, Nicky Gavron and Stephen Knight are urging the Mayor of London to defer his decision on the Earls Court andWest Kensington Opportunity Area - which includes the demolition of the Earls Court ExhibitionCentres.
Developers want to create four "villages" and a "high street" on a 77 acre site.
It's claimed the plans will create 7,500 homes and thousands of permanent jobs and take 20 years to complete.
The Assembly members say they believe that the economic case for retaining theEarls Court Exhibition Centres has not been properly considered and is in factunderstated.
In a joint press release they stated:
"These successful and established international Exhibition Centres attracts 1.5 million visitors, 15,000 exhibitors and 300 events each year, are estimated to be worth £1.25 billion to London’s economy and supports around 12,500 London jobs."
The Mayor is due to decide the joint planning application from Hammersmith & Fulham and Kensington & Chelsea before the 4th of July.