OTTAWA -- Police need special wiretap orders -- not just ordinary search warrants -- to intercept cellphone text messages as part of criminal investigations, the Supreme Court of Canada ruled Wednesday.

In a 5-2 split decision, the court sided with wireless carrier Telus (TSX:T) by agreeing that text messaging is essentially another form of conversation and should receive the same protection to which private communications are entitled under the Criminal Code.

"Text messaging is, in essence, an electronic conversation," Justice Rosalie Abella wrote for the majority of the court. "Technical differences inherent in new technology should not determine the scope of protection afforded to private communications.

"The only practical difference between text messaging and traditional voice communications is the transmission process. This distinction should not take text messages outside the protection to which private communications are entitled."

The case arose out of Owen Sound, Ont., after the Ontario Superior Court granted police a general warrant that ordered Telus to turn over any text messages sent or received by two of its customers between March 18 and March 30, 2010. The warrant also compelled Telus to provide police with copies of the customers' texts every day for the following two weeks.

Unlike many other wireless carriers, Telus stores copies of all text messages sent or received by its subscribers in a computer database for 30 days.

The company argued that even though copies of the messages were kept in a database, police would still be "intercepting" the communication by seizing the texts and would therefore need to get a wiretap order, which is more difficult to obtain than a general warrant, because of privacy provisions in the Criminal Code.

The federal Crown said that would clog the courts with thousands of wiretap applications each year.

Telus lost its initial bid to quash the warrant and appealed to the Supreme Court. The company's lawyers argued police need wiretap authorization under the Criminal Code to seize private text messages.

"The intrusion on a person's privacy is identical whether the police surreptitiously listen in to your conversations while they are occurring or surreptitiously read copies of your private communications that are obtained directly from the means required for delivery of the communication," they said in written arguments.

The case split the court.

Justices Abella, Morris Fish and Louis LeBel said there needed to be a broad interpretation of the Criminal Code section that deals with authorizations for wiretaps to intercept private conversations, "to ensure that the general warrant is not used presumptively to prevent the circumvention of the more specific or rigorous pre-authorization requirements for warrants."

"The interpretation should not be dictated by the technology used to transmit such communications, like the computer used in this case, but by what was intended to be protected under Part VI" of the Criminal Code, Abella wrote.

Two other justices -- Michael Moldaver and Andromache Karakatsanis -- agreed for different reasons. They felt police failed to show there was no other provision of the Criminal Code or any other law they could use to obtain the text messages to justify the general warrant.

"The investigative technique in this case was substantively equivalent to an intercept," Moldaver wrote. "The general warrant is thus invalid."

Justice Thomas Cromwell and Chief Justice Beverley McLachlin also agreed that text messages are private conversations. But where they disagreed was over the notion that police had intercepted communications. Police only sought copies of messages kept in the Telus database, Cromwell and McLachlin wrote, not conversations as they were actually happening, so a general warrant was appropriate.

Canadians sent and receive billions of text messages each year, according to industry figures. Wednesday's ruling effectively sets new rules for how the authorities can access electronic conversations.

"It clarifies that the courts will approach new communications technology with the same eye towards protecting privacy as they do with old technology," Telus spokesman Shawn Hall said in a telephone interview.

"This will go a long way towards protecting Canadians' privacy, but still provide police access to communications with an appropriate degree of judicial oversight."

The Canadian Civil Liberties Association, which was an intervener in the case, also welcomed the ruling.

"We see it as a robust vindication of privacy rights in the digital age," said Abby Deshman, "and really upholding the privacy that we expect with traditional conversations over the phone and bringing that forward into an era of text messaging."

The case before the Supreme Court is one of several involving privacy concerns in an age of electronic communication.

Earlier this year, Ontario's highest court ruled it was OK for police officers to look through someone's cell phone if it is not password protected. However, the Court of Appeal for Ontario said a search warrant is needed if the phone has a password or is otherwise locked to anyone other than its owner.

The password case came after a man was arrested after a jewelry stall at a Toronto flea market was robbed, and police found pictures of a gun and cash as well as a text message about jewelry on his phone.