The provision is included in a federal bill that would require telecommunications companies to "build in" the capacity to intercept e-mail, Web surfing and telephone activity of thousands of individuals at a time.

Privacy advocates say the bill goes too far in building surveillance machinery without enough safeguards to protect the privacy of innocent people.

Deputy Prime Minister Anne McLellan argued that the bill will merely update existing law so that organized criminals and child pornographers can be placed under surveillance. She noted that court orders are still required before the police can conduct wiretaps on someone's phone or Internet communications.

But one provision, which would require Internet companies to hand over a variety of identifying information about subscribers, was attacked yesterday as giving police too much latitude to snoop into Canadians' private lives.

The information includes telephone numbers, addresses, e-mail addresses and IP addresses, which can identify a person's computer to the operator of a website that the person is viewing.

"There are no limits on it," said New Democratic MP Joe Comartin, the party's justice critic. "I don't think they should be entitled to ask for that unless it's part of an investigation and it should be authorized, as part of that investigation, through a judicial warrant."

Public Safety officials said the bill also prevents Internet companies from revealing how often the police request such information, although they said that the police must keep records and privacy commissioners will be able to review them.

That is a lower level of safeguard than exists for intercept warrants, however. The government must report how many such court orders are authorized each year; seizure warrants are made public after they are executed unless they have been sealed by a court.

The bill would require telecommunications companies across the country to build in capacity that, when combined, would be enough to conduct round-the-clock monitoring of the Internet or telephone communications of more than 8,000 people at a time.

The police can already obtain warrants to intercept e-mail and other electronic communication, but the companies that provide services such as e-mail are not always able to do the taps and transmit the intercepted communications to police as it occurs.

Ms. McLellan defended the bill.

"First of all, it's not a vast system. In fact, we are well behind other nations to which we regularly compare ourselves as it relates to the ability for law enforcement to intercept certain kinds of new technologies," she said.

Public Safety officials said that there have been "numerous" cases in which police investigations were blocked because Internet companies could not conduct taps, but they said they didn't have statistics on how often that has happened.

Mr. Comartin said that if the Canadian government were serious about combatting child pornography, it would enact tougher laws so that Internet service providers can act to prevent it.