A second student - a 19-year-old male - was arrested for fuelling a fire and would be charged, Dunedin police said.
‘‘We have absolutely nil tolerance for that sort of behaviour,'' Sergeant Ed Baker said. The Hyde St fire was one of several lit in the student quarter of the city just before 10pm, on the first night of the University of Otago's Orientation Week.
A firefighter at the scene in Hyde St said an ambulance was called and the student was given first aid.
Fire crews responded to eight calls from the student area in two hours from about 9pm, including twice to Hyde St in quick succession.
Willowbank Station Officer Stephen Clarke said his crews had attended two of the fires last night - one of a chair in Forth St, and the other in rubbish in Castle St.
He believed much of the packaging students used while moving into their flats was the source of material for the fires.
While the Hyde St fires attracted crowds of students, elsewhere students stayed on their own properties.
Mr Clarke said the mood of the crowd was ‘‘quite friendly'' - unlike last year's so-called ‘‘student riots''.