The lorry, which was carrying about 20 tonnes of baled straw, was heading north near Markham Moor when the blaze broke out.
Nottinghamshire Fire and Rescue Service sent crews from Retford, Tuxford and Worksop fire stations to tackle the blaze, following the call this morning.
A service spokesman said: “Motorists should be warned they are probably going to be there for quite some time.”
Traffic is reported to be slow in both directions and highways engineers are working on diverting northbound traffic to use part of the southbound carriageway.
The congestion is said to be worst between the A57 junction at Retford and the B6387 junction at Dover Bottom, Elkesley.
Bus operator Stagecoach has also announced its services are being diverted in the area.