Amec and Balfour Beatty intend to enter an alliance to compete for the contract, known as the Allenby & Connaught scheme. They will be up against a link-up between Bovis Lend Lease and Amey.
The joint ventures are necessary because of the size of the project.
One source close to the contractors said: "The scheme is so vast, the cash flow will be horrendous for any individual company. There is a lot of jockeying for position among the big contractors for the scheme."
It is understood that the barracks will be procured under the PFI rather than the MoD's usual prime contracting route.
The scheme will provide apartments for army bases at Aldershot, Hampshire and Tidworth, Wiltshire. It is part of the army's move from shared accommodation to single, flat-like units, which will be fitted with ensuite bathrooms.
The project will include facilities management and the upkeep of the two estates.
There is a lot of jockeying for position among big contractors
Source close to the contractors
The Bovis Lend Lease–Amey team is expected to split the work, with the contractor looking after construction, leaving the services element to Amey. Bovis already has a joint venture with US fit-out and FM firm Actus for similar accommodation projects for the US military.
It is unclear whether the Amec–Balfour Beatty team will make the same arrangement or take one estate each.
Other contractors expected to be pitching for the project are Skanska, Carillion, Jarvis and Mowlem.
A source at one of the other interested contractors said it was waiting to see the full details of the contract before striking a possible joint venture partnership.
The scheme is due to be advertised in the European Union's Official Journal early next month.