"Both the Liberals and the NDP remain offside with Canadians who recognize the immense value of Canadian citizenship and the importance of protecting its integrity," Alexander said in a statement.
"It is shameful that activist immigration lawyers, who never miss an opportunity to criticize our government's citizenship and immigration reforms, are attempting to drum up business by promoting the interests of convicted terrorists and serious criminals over the safety and security of Canadians."
Bill C-24, the so-called Strengthening Canadian Citizenship Act, proposes a series of reforms to Canada's immigration system.
It was slated to go to second reading — essentially agreement in principle — on Wednesday after just two hours of debate, with voting on Thursday.
Under the proposed changes, citizenship can be revoked from dual nationals convicted of terrorism, high treason and spying offences, or who take up arms against Canada. As well, permanent residents who commit these acts will be barred from applying for citizenship.
Alexander has said the rule would only apply to those facing such charges in a Canadian court and that the government would not accept convictions from dictatorships.
The bill's provisions also require applicants to be present in Canada for a total of four out of their past six years, and 183 days per year for at least four of those six years.
Some critics have suggested that highly skilled immigrants who travel the world to find work will find it more difficult to meet such a test.
The bill also contains measures aimed at thwarting people who pay consultants to pretend they are living in Canada when they have no intention of ever setting foot in the country.
Alexander has said the changes are needed because the Citizenship Act hasn't been overhauled in 36 years. The government hopes the changes will help slash a backlog of citizenship applications that has grown to 320,000 files.
John McCallum, the Liberal immigration critic, said his party will vote against the bill Thursday, chastising the government for limiting debate to just two hours.
"I think it's obvious he doesn't want Canadians to understand this bill; the more Canadians do understand it, the less they'll like it," McCallum said.
"They're doing all sorts of things to increase the barriers to citizenship.... They suspect that everyone is some sort of criminal."
The NDP's Lysane Blanchette-Lamothe says her party will also vote against the bill.
"All the experts at the committee hearings agreed that this bill is probably unconstitutional," she said.
The two biggest areas of concern are the powers the government would have to revoke citizenship — without hope of appeal — based on convictions in other countries, and to withdraw citizenship from anyone who might have to leave Canada, Blanchette-Lamothe said.
"What if someone takes a job outside Canada, or has to leave Canada to take care of elderly parents?" she said.
"The minister can say that's not his intention, but the question is, is the bill well-written? So far experts say that it isn't, and have raised many concerns about it."
Follow Lee-Anne Goodman on Twitter at @leeanne25
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