Ontario's premier has entered the debate over Canada's new prostitution law a day after it took effect, adding her voice to a growing number of groups concerned for sex workers' safety and adding tension to her relationship with the Harper government.

Kathleen Wynne issued a statement Sunday saying she has a "grave concern" that the new rules dealing with the world's oldest profession won't be any better than the old system when it comes to protecting prostitutes from harm.

"I am not an expert, and I am not a lawyer, but as premier of this province, I am concerned that this legislation (now the law of the land) will not make sex workers safer," the statement reads.

Ontario Premier Kathleen Wynne, seen speaking in Ottawa earlier this year, has issued a statement about her concerns regarding the county's new prostitution laws. (Sean Kilpatrick/Canadian Press)

Wynne said she has asked the province's attorney general to advise her on the legislation's "constitutional validity" in light of the Supreme Court of Canada ruling quashing the old law, and for "options" in case its Charter compatibility is questioned, but stopped short of saying the province wouldn't follow the new rules.

"We must enforce duly enacted legislation, but I believe that we must also take steps to satisfy ourselves that, in doing so, we are upholding the constitution and the Charter."

Her remarks are a rebuke to the Tory government, which says the new law gives prostitutes the ability to create safer working conditions for themselves.

It's the latest flare-up between Wynne and Prime Minister Stephen Harper, who the premier says is refusing to meet to discuss issues of importance to the province. On Thursday, Harper chastised Wynne's government, saying it ought to focus less on "confrontation" and more on getting its fiscal house in order.

The sweeping new changes to the way prostitution is regulated in Canada follow the Supreme Court decision last year that found the old laws violated the rights of prostitutes.

The new rules criminalize the purchase of sex as well as things like advertising or other forms of communication related to its sale, while providing some legal immunity for sex workers themselves.

A spokeswoman for Justice Minister Peter MacKay defended the new law, saying it helps protect sex workers by letting them hire bodyguards or work from a regular indoor location.

"Police, communities, and women's groups have welcomed our approach. Canada is not alone in proposing laws that view prostitution as exploitation," Jennifer Gearey said in an email.

As the sex-law shift took effect Saturday, more than 60 organizations and agencies from across the country made a call for its non-enforcement and repeal.

The head of one of those groups said she was "heartened" by Wynne's statement, but called on the premier to do more by seeking a court reference on its constitutional status and refusing to enforce the law.

"I hope that Premier Wynne will take a stand for the human rights of sex workers by recommending a policy of non-enforcement within her provincial jurisdiction. For her to leave sex workers behind would be shameful," Jean McDonald, of advocacy group Maggie's, said in an email.

"Sex workers should be able to work freely and safely, with the full protection of labour and criminal law. We need the full decriminalization of sex work in order to ensure the safety and security, dignity and well-being of those involved in the sex trade."