AUSTRALIAN ultra-marathon man Pat Farmer has completed his epic run from the North Pole to the South Pole in a feat of endurance he said would take its toll on his body for as long as he lived.

The 48-year-old former politician set off from the North Pole on April 2 last year with the emotional Farmer finally planting a Red Cross flag 21,000km later at the world's most southerly point.

His run was dedicated to highlighting and raising money for Red Cross water and sanitation projects and he said the thought of people worse off than himself kept him going through periods of extreme hardship.

"I've endured a lot on this run, but the people of Africa and East Timor and South America who have no clean water or have been victims of flood, earthquake, fire and famine do it very tough too," he said from Antarctica.

The run from the world's most northerly tip to its southernmost took in 14 countries and conditions from freezing ice wastes to mountains and sweltering tropics.

He said he endured snow blizzards, became lost in the blazing deserts of Peru, dodged polar bears, snakes, crocodiles, armed bandits and rogue militias, and narrowly avoided being wiped out by an out-of-control truck.

Running an incredible average of 80km every day, with no days off, he suffered dehydration, stress injuries and pushed through what he said was unimaginable pain to raise about $100,000.

"This run will take a toll on my body for as long as I live," said the father-of-two.

"But every step, every frustration, and every moment when I've considered, but rejected the thought of lying down and not running another kilometre, has been worth it.

"Running long distances is my gift, my way of making a difference."

Farmer has put himself through the pain barrier many times before, holding seven world records, including the fastest run around Australia - 15,000km in 191 days.

The ultra-marathon athlete has twice crossed Australia's desert centre on foot and also raced across the US, finishing fourth despite 50 days of running with a fractured leg.

"Pat Farmer is an inspiration to all humanity," Australian Red Cross chief executive Robert Tickner said, praising his "amazing feat of physical courage and endurance".

