The road is shut in both directions between junctions 3 at the Staygate Roundabout and 2 for the Euroway Trading Estate.
Highways Yorkshire said: " The M606 is closed in both directions between Junction 3 (Odsal) and Junction 2 (Euroway Trading Estate) for a police-led incident
"West Yorkshire Police lead the response to the ongoing incident and have closed the carriageway to allow them to work at scene. National Highways have resources in attendance to assist with traffic management.
"Delays are likely on approach to the closure and diversion routes.
"If this closure impacts on your planned route, please allow extra journey time. Plan ahead, you may wish to re-route or even delay your journey."
West Yorkshire Police have been contacted for further details about the nature of the incident.