Traffic was stopped on the M60 near Stockport following reports of a pedestrian on the road.
Police said the carriageway had been temporarily shut clockwise between junction 2 for Cheadle and junction 3 for Wilmslow just before 1pm.
Officers were called earlier in the afternoon following a number of sightings.
Drivers said the pedestrian was in the central reservation.
No further details have been released about the incident.
It is unclear at this stage when the road will reopen to traffic, but the closure was described as a 'rolling roadblock', meaning it is only temporary.
At 12.50pm on Monday, North West Motorway Police tweeted: "Rolling road block at junction 2 to junction 3 of the M60 clockwise due to a number of reports of a pedestrian in the central reservation."
