The motorway is closed westbound between J26 Nenagh West and J27 Birdhill due to a multi-vehicle collision. Gardaí say it’s likely to be closed for a number of hours.
Weather conditions were said to be very poor at the time.
Traffic is heavy in the area with Gardaí advising motorists to use an alternative route.
Meanwhile the eastbound carriageway has reopened following a separate collision at J27.