"I saw people lying on the ground being helped by medics at three different spots on the track," she said yesterday.
"It looked like one woman had collapsed just past the highest point of the harbour bridge - she was being helped onto a stretcher by St John ambulance staff.
"Another man, who looked quite young, was being stretchered away from the track just 3km from the finish line. He was as white as a ghost."
Another competitor taking part in the 12km traverse said she saw St John ambulance staff attend to a man, a racer, on the ground in Halsey St.
A woman at the start of the traverse fell and scraped her face, the woman said.
One runner competing in his 349th marathon was working against another challenge - doctor's orders.
A spokesperson for Ironman said the safety and welfare of runners is their primary concern in all of their events and the Auckland Marathon is no different.
"While any hospitalisation is one too many, six such hospitalisations is not out of the ordinary, for an endurance event of this nature with in excess of 15,000 participants," they said.
"In 2017 we had seven such transportations for hospital treatment, with approximately 1000 fewer athletes.
"At every event, we follow up with each athlete (and/or family) that has been taken to hospital to offer our support and assistance.
"This process was followed on Sunday and in the time since the event."