Fees from international students are becoming increasingly crucial to the bottom line at universities across Ontario, research by CBC News reveals.

Encouraged by the provincial government, universities have ramped up their international recruitment in the past few years, resulting in rapid growth in the amount of money that foreign students are pumping into the system.

The number of foreign students attending university in Ontario increased 88.5 per cent over six years, starting in 2010, according to figures provided by the Ministry of Advanced Education and Skills Development. During the same period, enrolment of domestic students grew just seven per cent.

Total revenue from international students' tuition fees more than doubled in a four-year stretch, shooting upward from $620 million in 2011-12, to $1.28 billion in 2015-16, the most recent year for which statistics are available.

"They're using international students as cash cows, unfortunately," said Nour Alideeb, chairperson of the Canadian Federation of Students – Ontario.

Alideeb believes there is a direct correlation between reduced provincial government funding to universities and sharply increased tuition fees to foreign students.

Universities "add international students to top up the amount of funding that they're actually missing," Alideeb said in an interview with CBC News.

The total operating grant provided by the province to Ontario universities has effectively been frozen for the past decade, increasing only with inflation, while revenues from foreign students have shot up.

"Universities are relying more and more over time on tuition revenue versus government grants," said the Council of Ontario Universities in its most recent financial report for 2015-16. The report shows grants have dwindled to make up just 40 per cent of operating revenue, down from 46 per cent in 2011-12.

Pratishtha Kohli did her undergraduate degree as an international student at the University of Toronto and is working on her master's degree at the Ontario Institute for Studies in Education. (Hart House)

While tuition fees for domestic students are regulated, Ontario's universities can charge foreign students whatever they want. The average tuition for international students in undergraduate arts and science programs across Ontario is $23,510 — nearly four times as high as the equivalent for Canadian students ($6,327).

The University of Toronto's tuition fee for international students starting their undergraduate arts and science programs was $41,920 last year, compared with $6,400 for domestic students.

"It definitely doesn't feel fair to have such a huge discrepancy," said international student Pratishtha Kohli, who is working on a master's degree at the Ontario Institute for Studies in Education, at U of T. "It's not like I get any preferential treatment."

Kohli was born in India and lived in the Philippines, Malaysia and Hong Kong before coming to the University of Toronto for an undergraduate degree in psychology and criminology.

Foreign students now provide more than half of U of T's $1.3 billion in tuition revenue, according to the university's 2017-18 budget documents.

U of T sets its fees with a close eye on what other research-intensive universities around the world charge, and with consideration for international students' extra requirements, said Richard Levin, the university's executive director of enrolment services.

"There are extra supports, there's help with language, there's additional orientation," Levin told CBC News. "It's important that the university provides a really good experience for international students if we want to continue to recruit them."

Applications from international students have roughly doubled in the past five years, said Levin. "We have been putting effort into recruiting around the globe, as we do domestically, so I think we're seeing some of that paying off."

Richard Levin is university registrar and executive director of enrolment services for the University of Toronto. (CBC)

Foreign students now make up 25 per cent of the incoming class at U of T and the proportion is not projected to rise beyond that, said Levin. International students are not taking away places from Canadians, he said.

"International students really enrich the experience for everybody," said Levin. "If you think about being a student from Ontario and coming to U of T and getting to be in a classroom where you might meet students from the U.S. and Africa and China, that's just a very enriching component of your education, regardless of what you're studying."

Research by the federal government estimates the economic impact of international students in Canada at about $11 billion annually, with about $5.4 billion of that spent in Ontario.

The provincial government has been working on a post-secondary international education strategy since early 2016 and officials say they plan on it being complete this fall.