Thousands of international students planning to study in Canada might not be here when classes start in September because of a slowdown processing visa applications outside the country, warns the Association of Atlantic Universities.

The group is asking the four Atlantic premiers to lobby the federal government to do what it can to end a work-to-rule campaign by the workers who handle visa applications.

It says schools' reputations are suffering.

"It's a big concern, not just here but right across the country," said executive-director Peter Halpin.

The federal government and the union representing diplomats and immigration officers abroad have been locked in a contract negotiation battle for months. As part of escalating job action measures, diplomats at key visa application centres — including Beijing, Delhi, Sao Paolo and Mexico City — have withdrawn their services.

International students make up an increasingly important and lucrative part of the university student body.

Halpin said the number of foreign students studying in the region is now close to 11,000, up 12 per cent compared to the previous year.

"The international marketplace for international students is fiercely competitive so if those students are unable to get through visa process in timely manner there’s a very strong possibility they'll find alternative country and university to attend," he said.

"It is creating a certain degree of anxiety because our universities put a great deal of energy, time and resources into the recruitment of international students from over 150 countries around the world. So anything that deters those students from selecting our universities and our region as a place to study is a significant issue."

Halpin says he hopes the contract dispute is resolved soon, otherwise students might go to other parts of the world.

It's not just students waiting to come here who are facing delays.  International students who want to work in Canada are hindered by backlog issues.

"It's kind of disappointing and also I feel it’s kind of overwhelming too because you know there’s opportunities out there and the fact that that there’s one single door and you don’t have a  key to that door," said Yannick Manga, a student at Saint Mary’s University in Halifax.

"My employers expect me to have the work permit by September because they are going to call me back for a potential job position. If I don't have it, it impedes me to go forward and say ‘I am also eligible for the job,’"

There are no planned talks between the union and the federal government.