The Irish Coastguard is currently undergoing a long range mission over 100 miles off the southwest coast.
The coastguard received a call from the Swedish-registered ship about a "critically ill crewman" on board last night.
The operation is currently underway 100 miles south of Fastnet Rock off the south-west coast of Cork, as Met Eireann issue five separate weather warnings ahead of the weekend.
Waterford-based helicopter Rescue 117 is currently attending the scene to undergo a medical evacuation.
"We have a Shannon-based helicopter also involved as it's a long-range mission," an Irish Coastguard spokesperson said.
"The Shannon-based helicopter will provide top cover support and keep communications flowing," he explained.
"Our Valencia-based coastguard is coordinating the mission.
"The mission is ongoing as strong gale-force winds are now expected."
The coastguard have been in contact with the ship since the emergency call last night, but had to wait until the ship came into range before they could begin the operation.
Helicopters departed for the vessel at approximately 9.30am and was due to arrive at the scene at 11am.
The hospital the crew member will attend has not yet been confirmed.
The vessel is on course to Liverpool and was last at port in Newark, USA on November 22.