A firefighter standing on the back step of an antique fire truck was seriously injured.
Fergus Keith, a volunteer at the Omokoroa brigade, suffered two broken legs.
"He was standing on the rear step of one of the vintage trucks. With the nose to tail he was stuck between the two vehicles," a fire official told New Zealand reporters.
A St John Ambulance spokesman said Keith was taken to Tauranga Hospital for treatment. His wife said fellow firefighters and family have been supportive.
"It was supposed to be a day of celebration and it's quite unpleasant when one of your guys gets injured," the fire officer said.
Te Puke deputy chief fire officer Dale Lindsay said the incident put a "rather large damper" on the weekend's celebrations.
The road was reopened sooner than expected after the parade and a car "appeared to whiz through" the roundabout forcing the front fire truck to stop suddenly but the second fire truck did not stop in time.