Gardaí are at the scene of in incident at a scrap yard on the Greenhills Road, Walkinstown which occurred at approx. 11:35am.
A man aged in his early 40s received an apparent gunshot wound during the incident.
It is reported the suspect entered the premises armed with a shotgun and fled the scene on foot.
The victim has been taken to Tallaght Hospital were his condition is unknown at present.
It is believed that the victim was not the intended target.
Gardaí are appealing for anyone who was in the area or who has any information to contact Crumlin Garda Station 01-6666200, The Garda Confidential Line on 1800-666-111 or any Garda Station.