It is understood that the client, Wembley National Stadium, has reached preferred bidder status with one of the consortia on the three-team shortlist, and is close to agreeing a guaranteed maximum price deal.
A Wembley insider said: "We're in serious negotiations with one party now. Once appointed, it will have five months to negotiate whether the contract will be design-and-build or a straight guaranteed maximum price. Once it has done that, we could split the package into two or three, or keep it as a single entity. Whatever we do, it will be a fixed price."
However, the insider added: "If we don't get the type of deal we want from the preferred bidder, we'll go back to the marketplace in the summer and maybe bid the project differently. But we're confident we can complete a deal now."
The final three contenders for the scheme are teams including Bovis Lend Lease/Multiplex, HBG and Mowlem.
None of the shortlisted companies would comment, but some industry insiders have tipped the Bovis Lend Lease/Multiplex consortium as favourite. Multiplex was the contractor for the Sydney Olympic stadium
One said: "They are definitely worth a bet. With Lend Lease, they have the financial clout and also the development back-up to deliver the government's plans to regenerate the area around Wembley – as well as having the stadia expertise."
A number of major contractors, including Sir Robert McAlpine and Bouygues, have already pulled out of the bidding. It is understood that their reasons for withdrawing were the onerous contract conditions imposed by the client.
It is also understood that Wembley refused to allow contractors to bid the project in two stages, insisting that it was bid as a lump-sum project.
One contractor described Wembley National Stadium as "the client from hell". Another said: "It does not seem to have heard of the concept of partnering, let alone Egan."
The project to redevelop the stadium has been beset with difficulties. The original stadium design had to be altered, and he plan for a proposed athletics track was scrapped after it was deemed unsuitable for a British Olympic bid. The stadium is set to get planning approval later this month.