The Welsh Government will use an early contractor involvement (ECI) procurement route for the M4 relief road.
The controversial project was given the green light by Welsh Transport Minister Edwina Hart last week.
The Government has now formally launched the bid process, and will use the EtenderWales portal for the prequalification exercise. The deadline for bidders is 18 August.
Five firms are expected to be shortlisted for the tender stage.
The ‘black route’ approved by Hart runs to the south of Newport, between junctions 23 and 29, and includes a new bridge over the Usk. The 23km three-lane motorway connects Magor and Castleton.
The project is valued at between £700m and £800m.
Construction is not expected to start until 2018, and is scheduled to take three and a half years.