Speaking from New York, she said the start line at Staten Island was "completely stuffed".
"The marathon is such a celebration of life and we thought it's not going to be great to run it when so many people are hurting." Woodham said New York Mayor Michael Bloomberg had been "insensitive" to ask runners to dedicate the marathon to the victims of Sandy.
Doug Healey, 40, from Botany in Auckland, had been training for 10 months. He was going to help with the mop-up.
"Tomorrow we're going to go into central New York to see what we can do to help there."
Megan Green, 37, a property manager from Auckland, said the last-minute cancellation was a huge disappointment.
"People that have been training have made a lot of sacrifices."
Entrants have been offered a place in next year's marathon.
Former event winner Rod Dixon, who runs the Kidsmarathon Foundation - which educates America's 7-12 year-olds on good health and fitness habits to avoid obesity - said the organisers should have cancelled the race earlier.
"They [the organisers] should've told people around the world: 'Stay at home and send your love'. It was disappointing it took so long to come about but it was the right thing to do. I know for some of the runners it would be their race of a lifetime having done so much hard training but ... the city needs time to heal and rebuild."