The move will create 3,000 construction jobs when work on the new Forth road bridge gets under way next year.
The Scottish Parliament voted by 108-3 for the new crossing, which ministers said was required because of fears that corrosion of the Forth Road Bridge could force vehicle bans.
The two shortlisted bidders will now submit a final tender submission in January to meet a contract award timetable of Spring 2011.
The Forthspan consortium – which comprises Morgan Sindall, Bam Nuttall, Balfour Beatty and MT Hojgaard – is up against a joint venture of Hochtief, Morrison, Dragados and American Bridge International.
New transport minister Keith Brown said: “This is a huge step for a huge infrastructure project, the biggest that Scotland has seen for a generation.
“In approving the Forth Crossing Bill the Scottish Parliament has helped safeguard a strategically vital link in the transport network that will protect thousands of jobs and secure billions of pounds worth of revenue.
He added: “It has gone through planning, design development, consultation and parliamentary scrutiny in under four years and is on course to complete procurement and begin construction in 2011.”