The bidders will be interviewed on Thursday by Transport Scotland and each will have to demonstrate a strength in depth to manage a bridge or tunnel option for the crossing.
Firms in the fray are: Jacobs and Arup; Mott MacDonald; Cowie and Halcrow; Aecom and Scott Wilson; Gifford and Grontmij.
A decision will be made by the end of the year. The winner will act as the employer’s engineer on the high-profile project.
Transport Scotland announced last month that the option for both a tunnel and a bridge were still under consideration to replace the ailing Forth Road Bridge, which has been struck by premature cable corrosion.
This decision is despite reports by consultants Faber Maunsell and Jacobs recommending a cable-stayed structure.