Justice Minister Peter MacKay says the government’s new prostitution bill is constitutionally sound, but he fully expects it will be challenged again at the Supreme Court of Canada.

MacKay was the first witness today as a marathon round of hearings by the House of Commons justice committee on the Harper government’s new prostitution bill got underway.

The Supreme Court struck down Canada’s old prostitution law last December and gave the government a year to replace it with one that would comply with the Charter of Rights and Freedoms.

MacKay says the bill is sound law and is highly “defensible.”

He says it balances the need to protect communities from prostitution, including children, while protecting the prostitutes themselves, whom he says the government considers victims.

MacKay has said the government’s message this week is to pass the bill because there’s a sense of urgency.

MacKay has said he is open to amending the bill, but he’s dropping strong hints that will have limits.

“As sure as night follows day, there will be challenges when new bills are presented,” MacKay told the committee. “So we believe that the likelihood that it will be challenged is very real.”

He says the bill is constitutionally sound and is an adequate response to the Supreme Court.

Justice Department officials, who advised the government, will be open to questioning by all parties later today after MacKay has finished his testimony, says Bob Dechert, the minister’s parliamentary secretary.

Prostitution itself was actually legal in Canada under the old law, but most related activities — including communicating in a public place for the purposes of prostitution, pimping and running a brothel — were criminal offences.

The Supreme Court said that amounted to a violation of the basic Charter right to security of the person was concerned that the provisions unduly increased the risk to sex workers.

The Conservatives new bill creates new offences for clients and pimps, but does not criminalize prostitutes themselves.

It also cracks down on advertising and selling sexual services in public places where a child could reasonably be expected to be present.

Parliamentary committees rarely convene during the summer recess.

This week, the committee expects to hear from more than 60 witnesses over 20 hours of hearings that will run into Thursday.

NDP justice critic Francoise Boivin says she wants the government to slow down and thoughtfully craft a new, Charter-compliant law over the summer months.

The vast list of those testifying includes sex workers, indigenous women, community workers and experts from Europe.