It is thought that selection of the partners, for four-year partnering agreements, could take up to 12 months.
Pilots will take place in the North-west and West Midlands. Procure 21 will be rolled out on all publicly funded schemes worth more than £1m and all PFI schemes worth between £1m and £20m.
NHS Estates said details of Procure 21's selection and evaluation process would be released in due course.
Major Contractors Group chief executive Bill Tallis welcomed the move. He had earlier expressed fears that a general election could lead to further delays in the scheme.
Tallis said: "We would like to congratulate NHS Estates for the collaborative process it has followed before launching the scheme." Procure 21 has been criticised by small builders, who wanted the threshold raised to £4m. Medium-sized firms will be unable to tender for much of the work unless they enter the supply chain of a major contractor.
NHS Estates chief executive Kate Priestley had originally promised to launch the pilots early this year.