The M50 northbound is closed after Junction 6 Blanchardstown in Dublin after a truck went on fire.
Emergency services are being sent to the scene.
Gardaí are asking people to avoid the area.
The AA says traffic is heavy on approach from before Junction 7 Lucan.
Diversions are in place via the off and on ramps at Junction 6.
Traffic disruption on the M50
There are also delays northbound exiting the M50 at Junction 11 at Tallaght, Junction 10 Ballymount, Junction 9 Red Cow and Junction 7 at Lucan.
Traffic is also heavy on the M50 on ramp at Junction 9. Southbound traffic is slow from Junction 17 M11 through to the Bray North exit on the M11 itself.