As a result, the lawyer who successfully challenged the ruling on behalf of sex-trade workers said he had no choice but to try to appeal the ruling that also upheld the ban on street prostitution.
In response to a challenge from three sex-trade workers, Ontario's top court last month struck down the ban on bawdy houses on the basis that it increased the dangers prostitutes face because they are forced to work outside.
The five appellate justices also reworded the law against living on the avails of prostitution to clarify it would only apply in cases of exploitation because it could otherwise apply to people such as a prostitute's bodyguards, accountant or receptionist.
In its application to the Supreme Court for leave to appeal, the federal government said the Ontario Court of Appeal judgment creates a "legislative void."
"This represents a fundamental shift in criminal law and social policy in respect of provisions that have been in force, in some fashion, since prior to Confederation," the application states.
It also has an impact on police and prosecutions, both inside and outside Ontario, the government brief states.
Sex-trade workers, who hailed the Ontario court ruling as a recognition of their rights and said it would enhance their safety, expressed disappointment at Ottawa's decision.
Vancouver sex worker Amy Lebovitch called the federal government disrespectful toward prostitutes.
"We're telling them we need this to be safe and they're saying, 'Too bad'," Lebovitch, 33, said.
Toronto lawyer Alan Young, who acted for Lebovitch and the two other sex-trade workers, noted that six justices have already had their say.
"I'd like to see how the government of Canada gets around two very strong judgments that to me border on being incontrovertible," Young said.
The lawyer also said he would have been content to leave alone the Appeal Court ruling that upheld the ban on street soliciting but said he couldn't do that now.
"If we're going to be dragged to review those rulings, we might as well then appeal the ruling on communication because we always felt that law had many constitutional flaws."
Prostitution itself is not illegal in Canada, though many of the key activities were banned under the three laws considered by the Appeal Court.
In Ottawa, Justice Minister Rob Nicholson said the Supreme Court of Canada needed to create legal certainty by providing a binding, national ruling in light of last month's decision.
"Prostitution is harmful for society, as it exploits Canada's most vulnerable people, especially women," Nicholson told the House of Commons.
"Canadians can continue to count on this government to protect those who are vulnerable to this kind of exploitation."
The Ontario government announced it had decided, "after a careful review," to join the federal government in seeking to appeal.
Francoise Boivin, the NDP justice critic, said prostitution would continue regardless of the legal outcome of an appeal.
"We won't stop the black market," Boivin said. "There's so much work to be done in that file."
In its 132-page ruling, the Appeal Court found the bawdy-house ban too broad.
"The safest way to sell sex is for a prostitute to work indoors in a location under her control,'' the five justices ruled.
The court rejected Ottawa's contention that prostitutes knowingly choose an inherently dangerous occupation and therefore can't blame laws that might add to the risks.
The court suspended its ruling on brothels for 12 months to give Parliament an opportunity to draft a new law, and also put a 30-day stay on the altered living-on-the avails provision.
The federal government sought an interim extension of the stay on Wednesday, pending arguments on a longer stay, likely next month.
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