This Forbes-born bloke has run 50 marathons in 50 days, while continuing to work full time in his trade in Sydney.

That's more than 2100km since August 31, and he's raised more than $85,000 (at time of preparing for press) for Australian Red Cross by doing it.

Nedd shared to his public Facebook page that he's battled injuries throughout, yet he pumped out his 50th marathon in 2 hours 53 minutes - his first sub-three-hour time.

"How did I wake up every day and go again? I did it because I told myself I had a job to do and it was literally non negotiable," he wrote on his Facebook page.

He's run in the rain, in the dark, on the treadmill and around Centennial Park.

On his Facebook page, Nedd paid tribute to the many people who have joined him to pound the pavement, provided practical support and sponsorship and sent messages of encouragement.

At 6.15am Sunday he and a carload of friends turned up to run the 49^th marathon and found eight others ready to run with him.

"Community and being connected is everything, the money I've raised thanks to all you legends will do great things, but the most important part of all this is that it's brought people together and has turned a whole lot of people's lives around," he wrote.

To those who have contributed to his fundraising target, he wrote, ""From big to small, I appreciate every single dollar."

At the outset, Nedd told the Advocate that "if your why is bigger than your reason to quit, then you won't quit".

Nedd found his "why" confronted daily in Sydney by homelessness.

"It breaks my heart living in this beautiful part of the world that some people don't even know where there next meal will come from or worse, don't have a roof over their head," he said in his final post to his Nedd's 50 in 50 Facebook page.

"So many of us are simply lucky enough to be born into situations that mean we have those luxuries.

"Please, just be grateful for what you've got and the people you have around you.

"If you can, lend a hand, say hi to someone you wouldn't normally, hell, just smile. Guaranteed to make someone's day."

On Nedd's fundraising page, where you can still donate, Australian Red Cross advises: