The motorway is closed northbound between A57/A638 near Markham Moor and A57/A614 near Upper Morton after a blaze involving a lorry.
Police and other emergency services are on scene.
A Highways England spokesperson said: “This incident is still ongoing and the A1 will remain closed for some time.
"Diversion is via the A638 to Retford and to Scrooby then the A614 to rejoin the A1."