The prestigious venue has already suffered severe delays, with the original completion time of autumn 2005 put back to January 06 and then to March.
The 90,000 capacity arena's opening event - the Football Association (FA) Cup Final on 13 May (06) has been moved to Cardiff, Wales' Millennium Stadium, raising the question whether Bon Jovi will be able to go ahead with their 10 June gig.
A Wembley spokeswoman remains optimistic the American rockers' concert will go as planned, saying, "We're very hopeful the concerts will go ahead."
Wembley's chief executive MICHAEL CUNNAH says, "It's still too early to say when the stadium will be open."
On completion of the building work, stadium officials still have the lengthy task of training hundreds of staff and satisfying safety conditions required for staging major events.