The procurement process for the A556 bypass, between junction 19 of the M6 near Tabley and Knutsford and junction 7 of the M56 near Bowdon, has reportedly hit further delays as the scheme may have to go back out to public consultation.
The Highways Agency plans to include an extra 600 metres of road, surrounding the M6 roundabout, which was not initially included in the approved scheme.
The original plan, to build 5 km of new dual carriageway and involving the widening of existing road by 5 km, won 83% votes in its favour at a public consultation held six months ago. The project also gained approval from the transport secretary.
Officials had expected the roundabout to be improved as part of a £2.9bn project to widen the M6 along a 51-mile stretch between Birmingham and Manchester. However, it has now been switched to the bypass scheme.
Eight construction firms are understood to be in the running to complete the bypass project, which includes Balfour Beatty, Laing O'Rourke and Carillion.
The Highways Agency anticipates the job will cost up to £207m and take just over six years to complete. It hopes to invite tenders later this summer.