TORONTO -- Elections Canada has stopped enforcing a voting ban on citizens living abroad for more than five years in light of a court decision that struck down the provisions, the agency announced Tuesday.

In a statement, the voting regulator said those Canadians can apply now to vote in federal elections and byelections.

"The decision is effective immediately," the agency said. "Accordingly, Elections Canada will no longer apply those provisions."

As many as 1.4 million more Canadians are now eligible to vote, some of whom could end up casting ballots in the four byelections Prime Minister Stephen Harper announced for June 30.

Two Canadians living in the U.S. had challenged the rules that disenfranchised expatriates abroad for five years or more. They argued the provisions were arbitrary and unreasonable, and therefore violated their constitutional right as citizens to vote.

An Ontario Superior Court justice recently agreed with them.

In his ruling, Justice Michael Penny noted that mass murderers have the right to vote, but the long-term expats, "who care deeply about Canada," do not have the right.

Penny rejected government arguments that allowing non-residents to vote was somehow unfair to resident Canadians.

The Opposition New Democrats said on Tuesday the court and Elections Canada decisions don't go far enough.

They called for legislative changes to bring the Canada Elections Act into alignment with the rulings, which they hailed as a "victory."

"While the courts struck down the law, the legislation still reads as is," said New Democrat MP Megan Leslie, who previously introduced a private member's bill to make the required changes.

"Passing the bill would enshrine that right to vote in legislation."

A spokeswoman for Pierre Poilievre, minister of state for democratic reform, said the government was still studying the court ruling but noted it does not affect the controversial proposed Fair Elections Act.

As of now, Elections Canada said, Canadian citizens aged 18 or older who reside abroad may apply to be added to the international register of electors and vote by mail-in special ballot.

They do have to have lived in Canada at some point.

The agency said it would mail a special-ballot voting kit to all eligible electors on the register.

The rule disenfranchising Canadians abroad for more than five years was enacted in 1993 amid debate about the strength of their ties to Canada and their knowledge of domestic politics.

However, the five-year clock reset for those who returned even for short visits until 2007, when Elections Canada began enforcing the requirement for expats to "resume residency" to regain their right to vote abroad.

In their court challenge, Montreal-born Jamie Duong, 30, of Ithaca, N.Y., and Toronto-born Gillian Frank, 35, of Princeton, N.J., argued they retained deep ties and interest in Canada.

Expats pay about $6 billion in income taxes to the Canadian treasury, despite using fewer resources than their in-country counterparts, according to estimates.