UPDATE AT 8.45AM
AA Roadwatch said the N7 westbound has reopened between Newlands Cross and J2 Kingswood following a serious collision last night.
A serious collision on the N7 westbound near Kingswood has caused a full closure of the route.
The incident happened between midnight and 1am.
One witness reported seeing several ambulances, fire engines and Garda cars.
Motorists are being diverted through Clondalkin before re-joining the N7.
Witnesses reporting seeing ambulances, fire engines and several Garda cars.
AA Roadwatch said:
"The N7 westbound is closed between Newlands Cross and J2 Kingswood following a serious collision."
"The outbound / westbound lanes of the N7 (Naas Road) are currently closed to traffic from Newlands Cross to Junction Kingswood following a serious collision. Diversions are in place."