The completion of the new £757 million Wembley stadium, designed by Foster with HOK Sport, looks likely to miss its new September deadline for completion.
Australian construction firm Multiplex has said that it expects the construction work will not now be finished until a later date.
In a statement, it said 'certain works' had to be carried out by Wembley National Stadium (WNSL), the client, before the construction work could be completed. This would not happen before the deadline.
The statement from Multiplex says: 'In order to achieve practical completion of Wembley Stadium certain works which are the responsibility of WNSL rather than Multiplex must first be completed. WNSL has not begun some of these works.
'Furthermore, once practical completion has been achieved, it is the responsibility of WNSL to carry out a series of critical works and activities in order to make the stadium operational for events.'
'Multiplex is of the view that the works for which WNSL is responsible may not finish by September 2006 and therefore the date of practical completion may be delayed,' the statement concluded.
In March, bookmaker William Hill was offering odds of 7/2 that Wembley would not be ready for the 2007 FA Cup Final and odds of 1/6 that the stadium would stage the match.