The collision, involving a coach and a car, occurred at around 12.55pm.
The motorway was initially closed in both directions between junction 30 for Barlborough and junction 31 for Aston.
The southbound carriageway had been reopened by mid-afternoon but the northbound carriageway has only just reopened.
Police have not yet released any further details on the crash and the extent of any injuries is not yet known.