It was the second fatal collision in the region this weekend.
A five-year-old boy and a man in his 20s have died in separate crashes in the midlands.
Gardaí and emergency services attended the scene of a collision that occurred at Kilminchy, Portlaoise, on Saturday afternoon.
The collision involving a pedestrian and a car occurred at approximately 4.20pm.
The boy was taken to Midland Regional Hospital Portlaoise in a serious condition, where he was pronounced dead a short time later and a post mortem examination is due to take place.
A technical examination is due to be carried out by Garda Forensic Collision Investigators this morning.
Gardaí are also investigating a collision in Westmeath where a man in his 20s died in a crash involving a quad bike and a motorcycle.
It happened in Ballynascarry near Finnea at about 3.30pm yesterday.
The driver of the quad bike was pronounced dead at the scene.
A passenger on the quad bike, also in his 20s, was taken to the Tullamore Regional Hospital with non life-threatening injuries - while the motorcyclist, in his 30s, was rushed to the Mater Hospital in Dublin in a critical condition.
A forensic examination of the scene will be carried out today
Gardaí are appealing to anyone who may have witnessed either collision to contact them.
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