"I would like to acknowledge vice-chancellor Harlene Hayne, her team, and the university community for the resilience they have shown during an incredibly trying time.
"I also want to acknowledge the tireless efforts of both the investigation team, and the members of our staff who have been working in the community providing reassurance."
Otago University postponed all eight graduation ceremonies and parades until next year following a security threat.
Otago Vice-Chancellor Professor Harlene Hayne welcomed the news, saying she was pleased an arrest had been made but disappointed so many had missed out on their special moment.
"I am relieved there has been an arrest in relation to the security threat," said Hayne.
"I am extremely disappointed that these actions resulted in graduation ceremonies for more than 2,500 graduands and their whānau being postponed."
She said despite the arrest it was too late to reinstate graduation ceremonies that had been initially scheduled for tomorrow.
"Unfortunately, it is too late to change arrangements for tomorrow's graduations, which are postponed; however, we have many on-campus celebrations planned and I hope graduands and their supporters will join us to celebrate their academic achievements."
While all December graduation ceremonies were postponed, Hayne said a silver lining had been the way in which the university, graduates and their supporters had joined together to celebrate in a less formal way.
"I have been delighted to see the way that graduands and their families, friends and flatmates have overcome this disappointment and continued to take the opportunity to celebrate, marking their achievements in their own very personal ways.
"The manaakitanga of the student and Dunedin community has come to the fore and I know that everyone made the most of their special time here on campus. I wish all of this year's graduates nothing but the best and I thank them for their understanding and patience."
Hayne said the university was hugely appreciative of police who had worked tirelessly to achieve a result.
"We are extremely grateful to the police for their hard work, expert guidance and support."