The Canadian Association of Refugee Lawyers says it will fight the measures in the courts once the bill, which still needs Senate approval, becomes law.
The British Columbia Civil Liberties Association and Amnesty International Canada, though not part of the litigation, support the association's challenge.
The civil liberties association says it has not ruled out joining the legal action later.
Currently, someone may be stripped of Canadian citizenship for attaining it through false representations.
The federal bill would increase the scope to include those born in Canada but eligible to claim citizenship in another country — for instance, through their parents — and expand the grounds for revocation to include several criminal offences including treason and terrorism.
The legislation violates equality rights under the Constitution by creating separate classes of Canadians, said Lorne Waldman, president of the association of more than 250 lawyers who represent refugees.
The association also argues:
— the proposed revocation procedures lack the fairness of due legal process.
— a provision forcing new citizens to swear they intend to reside in Canada — and risk losing their citizenship if they later go abroad — would mean some Canadians have mobility rights while others do not.
Toronto lawyer Rocco Galati is also planning a constitutional challenge of the legislation, though on procedural rather than Charter of Rights grounds.
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