The venues in west London – which include Earls Court One and Earls Court Two – are subject to a major new development scheme now under consultation that will see them replaced with a series of "urban villages" and a new public park.
EC&O Venues commercial director Anna Golden said: "Organisers have been coming to us every day to ask us what is happening, but the one thing we cannot determine is the timescale."
However, she added that the earliest any development work can take place is after the last contracted business, which was in August 2012 – after the London 2012 Olympic Games, when Earls Court hosts the volleyball competition.
This earliest possible date has now been moved to at least September 2012.
"We are now starting to move that slightly and are looking at contracting business for September 2012," added Golden. "Commercially we are working with the organisers on the opportunity that Earls Court staying open will afford."
A public exhibition is set to open this week and run from 18-22 March showcasing the masterplan for the Earl’s Court Opportunity Area – which has been designed by Sir Terry Farrell.
EC&O Venues, which runs Earls Court and nearby Olympia, is hoping its £20m redevelopment at Olympia will allow events to relocate there from Earls Court.
Around 70 per cent of exhibitions will relocate to Olympia, said Golden.
She added that Olympia has a "good conference business", while at Earls Court, conferences account for less than a third of all business.
Santander this year moved to Earls Court from Olympia for its annual convention for 2,500 delegates in February and is looking at returning to the venue again in 2012.
"It was about variety," said Golden. "As all our organisers, Santander are well aware of the development plans and we will let them know once we know [the timeline]."
Around 150 of EC&O Venues staff are set to view the consultation exhibition from tomorrow.