38-year-old Niall O'Shaughnessy, who lives in Long Island, and his partner Moses Nelson were called to the scene on Monday morning.

A woman in her late 20s or early 30s was struggling to stay afloat on a lifebuoy. Realising she could soon go under the water, Niall dived into the 25ft deep Hudson.

“He kicked off his boots, clipped off his radio and jumped in,” an FDNY spokesman said, describing the rescue.

“He saw her having an incredible amount of difficulty and his brain took over. All that mattered was rescuing her.”

Moses Nelson says it is all part of their job.

"As a Rescue Paramedic, we are trained for this. We shouldn't be considered heroes, this is our job," he said.

#Happeningnow #FDNY Rescue Paramedics discuss rescue of a patient in the Hudson River this morning. pic.twitter.com/wVpD33xgdu — FDNY (@FDNY) July 20, 2015

Niall and the female were pulled to safety and she was rushed to Bellevue Hospital, where she is in a stable condition.

"I realized that she was exhausted and she was having a hard time handling the life ring properly" he said. "I was worried she was about to go under water for good.

"She was very nervous initially but I told her additional FDNY members were coming to help her.

"My biggest concern making sure she was OK and that she didn’t submerge. This was my first time I jumped in the water. I have no idea why she jumped in, my concern was to just get her out.

"Everyone in this job wants to help somebody, it's our second nature," he said.

This is not the first time Niall has put his own life at risk to help others. Last year he jumped onto subway tracks to save Mary Downey, an Irish woman who had become trapped between two train cars.

In that incident, he and an Irish firefighter kept the 22-year-old woman calm by discussing Ireland.

“Believe it or not, we had a laugh about it underneath the train,” he said at the time.

READ MORE: Irish connection leads to laughs during New York subway rescue