Pig lungs could be transplanted into humans following an Australian medical breakthrough bringing new hope to patients awaiting life-saving operations.

Until now pig organs have been incompatible with human blood, meaning the blood would clot almost immediately and could not pass through the lungs.

But scientists at Melbourne's St Vincent's Hospital were able to remove a section of swine DNA called the Gal gene and add human DNA to control blood clotting and rejection in humans.

They have kept pig lungs functioning with human blood, paving the way for animal-human transplants — called xenotransplantation — in as little as five years.

Dr. Glenn Westall said the discovery made in the past three months meant pig-human lung transplants were a real prospect.

"The blood went into the lungs without oxygen and came out with oxygen, which is the exact function of the lungs," he said.

"This is a significant advance compared to the experiments that have been performed over the past 20 years."

Approximately 900 lung transplants are performed each year in the United States, according to the Cystic Fibrosis Foundation.

Click here to read more from Courier Mail.