Lincoln University set up a quarantined examination room so students affected by an outbreak of gastroenteritis could sit their exams on Saturday.
The university says 15 students diagnosed with the infection were isolated in one area of the campus.
The university says students who were too sick to sit the exams could apply for dispensation.
A spokesperson for the Canterbury-based university, Charlotte Mayne, says there is no concern that students are faking the symptoms.
She says the exams are just one part of a process involving long-term assessment.
The university has ruled out food poisoning after students living in both self-catering accommodation and in halls of residence came down with the illness.