They're angry about the Conservatives' move to legislate away a backlog of some 280,000 applications created before 2008.
The government announced the decision in its March budget, saying it's a necessary part of modernizing the immigration system.
But Toronto lawyer Lorne Waldman said he was immediately flooded with emails by people who were furious about the changes.
They'd followed all the steps they were told to take in order to come to Canada, he said, only to be pushed aside.
"The irony of that is this is a government that's constantly telling us that people shouldn't jump the queue," he said.
"We have all these people who went into the queue, paid their money, followed the law ... and now the government is saying it's too bad because we changed our mind."
Waldman is now representing at least 40 people who are challenging the decision to eliminate the backlog and want to force the government to process their application.
He expects more to join.
The government has said those who are having their application and related fees returned can re-apply under new criteria established for the skilled worker program in the last few years.
In addition to legal action, the pledge to eliminate the backlog has sparked the creation of a Facebook group and small protests in India, Pakistan and China.
A spokesman for Immigration Minister Jason Kenney said government is committed to creating a fast and flexible immigration system.
"The government is confident that the provisions in Bill C-38 to eliminate the federal skilled worker backlog will withstand any legal challenge," Alexis Pavlich said in an email.
But the government's efforts to deal with the backlog have crumbled in the face of legal challenges before.
A decade ago, Waldman was part of a legal team that successfully challenged the government's attempts to regulate the backlog away by applying retroactive changes to the points system.
The current effort to get rid of the backlog is included in the omnibus budget bill, Bill C-38, which the government is aiming to pass in June.
As it is unlikely a court could hear the immigration cases before then, Waldman says he expects to ask the court rule that the government must keep their files open until the cases can be heard.
The seven-year backlog represents people who applied to get into Canada before Immigration Minister Jason Kenney rejigged the federal skilled worker program to fast-track applications from people the government felt could fill holes in Canada's economy.
The length of time it was taking to process the backlogged applications is the subject of another lawsuit involving over 700 people from around the world.
A hearing for that case has been set for June 5.
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