Roads and Maritime Services confirmed work on the overtaking lanes near Fullers Rd at Finley would start tomorrow.
The creation of the southbound lane, about 4km from Finley, will impact on traffic.
Both the northbound and southbound lanes will be reduced to a width of 3.2 metres, road shoulders will be closed and concrete safety barriers will be installed.
Work and partial road closures are expected to continue until at least August.
Heavy vehicle drivers are advised signs and wide load bays will be located at both ends of the construction area.
For safety reasons, speed limits will be reduced significantly during working hours - 7am to 6pm weekdays and 7am to 5pm Saturdays - and will be 80km/h at all other times.
Four of the 30 overtaking lanes proposed for the entire length of the Newell Highway will be created in the Southern Riverina region.
Other overtaking lanes will be installed at Chinamans Rd, north of Tocumwal, Mills Rd between Finley and Jerilderie and Bundure, north of Jerilderie.