Teachers at an international English school in Halifax say a job action campaign by visa officials in Canadian offices overseas is affecting international students preparing to come to Canada and whittling down its classrooms.

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 have scaled back some of their services.

There are about 180 students now studying at the International Language Institute. In other years there have been as many as 300.

The school said international students come to the Halifax campus to learn English before they go to university or write their Test of English as a Foreign Language or International English Language Testing System exams.

Marketing director Chris Musial said the visa delays have hurt Canada's reputation as a good place to learn and could take years to recover.

"The word that comes out to international recruiters and to students is that Canada is an unreliable partner when it comes to visa processing. We’re going to feel the effects six months from now, a year from now even two years," he said

"We’re competing with London, England and New York City."

Saudi Arabian student Ammach Al Anazi said potential foreign students will go elsewhere if the visa woes continue.

"They can’t come to Canada. They are stuck. They just wait to come to Canada. They think about going to the U.S.," he said.

The ILI is one of many schools suffering from visa delays.

Nova Scotia's universities have already expressed concern that thousands of international students planning to study in Canada might not be here when classes start in September.

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