"I need to restate there are residual risks that remain in terms of the stadium being able to hold the FA Cup final in May," said Multiplex's managing director in Britain, Martin Tidd.
"My view would be a 70 percent chance of completion for the cup final." The FA has made back up plans to hold the game at the Millennium Stadium in Cardiff, Wales which has staged the Cup final every year since the original Wembley closed in 2000.
Tidd said the company would inform Wembley National Stadium Ltd. within three weeks if the final could be staged.
"We have 3,500 guys out there putting a huge amount of pressure on the contractors to drive the job over the line," Tidd said.
"There's still a risk, we are managing it, but there may be other contractors out there that might not see it through."