Delays to completing Wembley stadium and other business factors will cost developer Mutiplex £70m, it has said.
The football world is waiting to see if the stadium is ready for May
Problems surrounding English football's showpiece arena were likely to leave it in a "substantially adverse" position from previous predictions for 2006.
The Australian firm, which this summer warned of tough times ahead, said it hoped to complete the project in time.
Multiplex shares fell sharply following the warning, dropping 8.46% to 3.16 Australian dollars ($2.35; £1.33).
Last month Multiplex had predicted annual earnings of around £90m.
"Multiplex has again disappointed - how often did they say in the last three months everything is okay but now they're saying Wembley is going to have a substantial impact on 2006 profits," said Ric Klusman, Aequs Securities' head of institutional trading.
While the firm warned Wembley would have significant impact on profits, it did add it still hoped to have the flagship project completed in time for May's FA Cup Final.
"Multiplex continues to target completion of the Wembley stadium to enable the 2006 FA Cup Final to be played, with progressive handover of parts of the stadium expected to commence from 31 January, 2006," it said.
Difficulties with the redevelopment of the 90,000-seat stadium prompted the resignation of Multiplex founder and executive chairman John Roberts in Mayas the group blamed "cost blow-outs" for the spiralling cost of the stadium.