A man has been airlifted to hospital after he was recovered from the Shannon Estuary during a major search operation this morning.

The man is understood to have been in the water for almost two hours and was spotted by the crew of the Waterford based Irish Coast Guard helicopter, Rescue 117.

The alarm was raised shortly after 9.00am when a person was reported 'overboard' from the Killimer to Tarbert ferry. The vessel immediately commenced a search of the area while the Irish Coast Guard was alerted.

Watch officers at the Coast Guard's marine rescue coordination centre on Valentia Island in Kerry mounted a significant search and rescue operation.

The nearby Kilrush RNLI inshore lifeboat (ILB) was mobilised while the Kilkee unit of the Irish Coast Guard dispatched a team by road to assist in the search.

Rescue 117 was tasked from its base in Waterford while the Fenit RNLI all-weather lifeboat (ALB) was also requested to make their way to the scene along with the Ballybunion Sea and Cliff Rescue unit and Ballybunion Coast Guard unit.

A number of vessels that were in the area, including several yachts taking part in a local event and the Shannon Pilot boat also joined the effort. Vessels in the area, which were in a position to assist in the search, were requested to do so.

Shortly before 11.00am, the crew of Rescue 117 reported seeing someone in the water a short distance west of the ESB's Tarbert Power station on the Kerry shore.

The helicopter's winchman/paramedic recovered the casualty and he was flown directly to University Hospital Limerick for treatment. The man is reported to be suffering from 'severe hypothermia.'

Once it was confirmed that the casualty had been located, the search operation was stood down.