George Grant, who works at Mitre 10 Mega in Hastings, is finding an alternative way to do the Mega Walk and support CanTeen.
He completed the 28km Mega Walk in 2015 and 2016, but was unable to do it this year because it clashes with his wedding anniversary.
"My wife would kill me," he told Hawke's Bay Today.
Mr Grant decided to do the walk this Monday at 7am instead - on a treadmill at Mitre 10.
He planned to walk on the treadmill for 60 minutes at a time, followed by five-minute breaks, hopefully walking 28km by noon.
"I went for a walk the other day on the treadmill. It's harder in a way because there's no one to talk to and nothing to look at."
Mr Grant's wife survived cancer, he said, and he has known many others affected by the disease.
She underwent radiation treatment and chemotherapy.
"It's very difficult to find somebody who hasn't been in some way affected by cancer.
"I got to a point in my life where I'd been extremely fortunate - my wife survived cancer."
He said the walk - which covered the distance from Hastings to Napier - was not difficult compared to what people with cancer endure.
"It's something that for me is a small thing to do."
Mr Grant hoped to raise awareness and promote the walk, and CanTeen, by completing the walk at Mitre 10.
He said it was his own stubbornness, more than fitness, that would get him through.
"I was born club-footed and I don't like to be told there's anything I can't do."
He has written the names of friends and family members taken by cancer on the high-visibility vest walkers wear, to remind him who he is doing it for.
The Mega Walk would be on Sunday, November 5, leaving from Mitre 10 Mega Hastings at 7.30am and ending at Mitre 10 Mega in Napier.
The Half Mega, Short Mega and Mega Meander were shorter options for those unable to do the full 28km.
All money raised from registrations and sponsorship goes to CanTeen, a charity that supports young people with cancer and their families.
Walkers can register at Mitre 10 or online at www.megawalk.co.nz