Kaitaia Abundant Life School student Travis Burrows will put his fitness to the test tomorrow on behalf of an ailing schoolmate.
Principal Mark Tan said a 5-year-old pupil, who was "really unwell", had been admitted to Auckland's Starship Hospital.
"I don't want to go into too much detail; suffice it to say that it is very serious, and we have to do what we can and all we can to support her and her family," he said.
"Our kids are getting right behind the family and doing what they can."
One student, Travis Burrows, had volunteered to walk around the school field 100 times, equating to around 20 kilometres, and was looking for sponsors.