Searches will resume in Ardnacrusha this morning after a body part was reported in the water.
Search crews were alerted following call from a passing motorist yesterday evening.
Emergency services were alerted around 3.30 yesterday afternoon after a motorist reported seeing an arm in the water under a birdge near Arnacrusha Power Station.
Search crews from Killaloe Coastguard, assisted by the Shannon-based Coastguard Helicopter and crews from Limerick Fire and Rescue service were dispatched to the scene.
Searches of the area continued for some time yesterday evening but no discovery was made.
Land and water searches are due to resume later this morning.