Students have also been advised that any policies placed after January 30 with the university's travel insurance provider, Allianz, would be deemed to have been booked "with awareness of the coronavirus".
Fraser said this week's decision was made to avoid the potential for students being trapped in countries, should international travel conditions change.
"Most are in low-risk countries, but there are some in regions such as Africa where things could change very rapidly," he said.
The decision was made by a senior group of faculty members – including infectious disease experts - responsible for delivering the international programme.
"We have been reviewing the programme for the past three months and monitoring global developments," Fraser said.
"The most important factor in Monday's decision was the spread of the virus into countries where monitoring and containment would be more difficult and where we currently have students."
He said the first priority was student welfare.
"This is not a situation that has ever happened before, certainly in my memory."
The Covid-19 crisis has already caused massive disruption to New Zealand universities.
Last month, Victoria University's vice chancellor Grant Guilford said universities could lose up to $300 million a year as long as New Zealand's current travel bans stayed in place.
More than 6500 Chinese students who were enrolled to study in New Zealand this year are still stuck at home.
