Every fortnight for the past 61 years, James Harrison has made his way from his home in Umina Beach on the NSW Central Coast to the Red Cross blood bank.

He spends half-an-hour with a needle in his arm giving blood - but his is no ordinary blood type.

The 81-year-old has a rare antibody in his bloodstream that is used to make a lifesaving medication called Anti-D, which infants need if they have an opposite blood type to their mother. If they don't have it the newborn could die.

Blood donor James Harrison, 81, holds a world record for the number of times he's donated since first beginning in 1957. Picture: 9NEWS. (9NEWS)

James' blood is in demand - so much so, that since 1957 he's made 1173 donations.

They don't call him the man with the golden arm for nothing, because in that time his blood has helped save more than two million lives.

It's a staggering story of a real life superman whose story has been told all over the world. But, because of his age, today is the last time he'll do it, and if it wasn't up to the doctors, he'd keep on providing it.

Mr Harrison has a rare antibody in his blood that makes it a highly demanded type among parents. Picture: 9NEWS. (9NEWS)

James is a very humble man who just wants to help, so he's saddened that this final day of helping has come.

"I've saved a lot of lives and brought a lot of new kids into the world. So that makes me feel good," he told 9NEWS.

"I increased the population by so many million I think."

The antibody, Anti-D, is given to infants if they have an opposite blood type to their mothers. Picture: 9NEWS. (9NEWS)

As impressed as anyone who has met him are the mums and dads whose baby has been saved because of James Harrison, who are the happiest.

Michelle Dibbs, her husband Edwin, and their little girl Eloise came to see James today for his final donation.

Eloise has a negative blood type and Michelle a positive blood type, therefore leaving the young mother needing two Anti-D injections before her little girl was born. It saved her life.

Due to his blood type being so useful, the 81-year-old has been back to his nearest Red Cross blood bank every fortnight for 61 years. Picture: 9NEWS. (9NEWS)

"I just wanted to say thank you. Thank you to James, he's a wonderful person," she said.

Back in 1951, James needed a lung removed. It was surgery that required someone else's blood which saved his life.

That was the spark James needed to save other people's lives - to pay it forward, but in this case, millions of times over.

In total, that means Mr Harrison has given blood to those who desperately need it 1173 times. Picture: 9NEWS. (9NEWS)

There aren't too many people in the world like James Harrison. A kind, caring man who has literally given so much of himself to save people.