The Federal Government's proposed changes to skilled migration rules threaten to inflict further damage on Australia's international education sector, according to the Greens.

Senator Sarah Hanson-Young, Greens spokesperson on Education, says there is nothing wrong with a Government review or tightening of the Occupations in Demand List, but that the timing and management of the move is questionable.

"Cancelling 20,000 visa applications without warning is not good policy or smart policy, it looks more like an act of desperation by the Government,'' Senator Hanson-Young said.

"Many people have come to Australia to put themselves through courses specifically identified by Australia as skills in demand - but now the rules have essentially been changed retrospectively, leaving these people stranded through no fault of their own.

"It would be much fairer if the Government allowed people to finish the visa application process they have started, but not accept any new applications.''

The Greens are concerned that Immigration minister, Chris Evans, has made these changes without taking into account the impact his decision will have on the international education sector, which provides Australia with its third-highest export earnings.

"Reports of conflict between the Immigration and Education departments over this policy shift will do little to convince people that this is anything other than policy on the run,'' Senator Hanson-Young said.

"These changes will likely lead to more students dropping out of courses, which will put even more strain on providers.

"The question is how the Government will ensure that Australia's reputation in international education will not be further damaged by the way these changes are carried out.

"Paying back 20,000 visa application fees will be a costly enough exercise, but neither the Government nor our economy can afford the cost of another crisis in confidence in the sector.''