OTTAWA - Canada's spy agency says it will use information extracted through torture if lives are at stake.

Geoffrey O'Brian, a lawyer for the Canadian Security Intelligence Service, said the agency will do so in the rare instances where it can prevent a catastrophic terrorist plot like the 1985 Air India attack or the 9-11 assault.

"The simple truth is, if we get information which can prevent something like the Air India bombing, the Twin Towers -- whatever, frankly -- that is the time when we will use it despite the provenance of that information," he told the Commons public safety committee Tuesday.

O'Brian said there will be "those occasional, unusual . . . almost once-in-a-lifetime situations" where such information -- even if gathered through coercion -- can be useful for national security.

He also said CSIS might unwittingly use information from torture "because the reality is in many cases you don't know" how it was collected.

O'Brian characterized those scenarios as exceptions to general practice, which ensures "we respect and follow Canadian values."

Liberal public safety critic Mark Holland said he was deeply disturbed by O'Brian's comments.

"We're sending the message today that if it's good enough, that if you torture them well enough and you get information that is marketable enough, then we're going to buy it -- we're in the market for information obtained by torture," he said.

"That's a dangerous message to be sending out there."

Many human-rights advocates say security officials should make no use of information from torture because it perpetuates abuse. They also argue that such information is inherently unreliable because victims will tell torturers anything they want to hear.

The Commons committee is looking at the government response to a federal inquiry into the Maher Arar affair and a more recent inquiry into the imprisonment of three other Arab-Canadian men.

Arar, a Syrian-born Canadian, was detained in New York in September 2002 and then shipped abroad by U.S. authorities -- ending up in a Damascus cell where he was tortured into giving false confessions about terrorist links.

O'Connor found the RCMP passed inaccurate and unfair information to the Americans that very likely led to Arar's arrest and deportation.

An inquiry led by Justice Dennis O'Connor made 23 recommendations on information sharing, training and monitoring of security probes -- several of them aimed at CSIS and the RCMP.

He said policies must include specific directions "aimed at eliminating any possible Canadian complicity in torture, avoiding the risk of other human rights abuses and ensuring accountability."

O'Connor also said information should never be provided to a foreign country where there is a credible risk that it will cause or contribute to the use of torture.

A second inquiry, led by former Supreme Court justice Frank Iacobucci, found Canadian officials had a hand in the torture of Abdullah Almalki, Ahmad El Maati and Muayyed Nureddin in Syria through the sharing of information with foreign intelligence and police agencies.

False confessions extracted under torture from El Maati were used to justify a telephone wiretap in Canada.

Iacobucci blamed CSIS, the RCMP and Foreign Affairs for various mistakes.

O'Brian declined to talk about Iacobucci's findings because El Maati and the other two men are suing the federal government.

Kerry Pither, a human rights activist who has written about the cases, was disappointed by the committee testimony.

"The agencies are very clearly trying to sidestep any accountability around the findings of the Iacobucci inquiry by sending people here today who say they can't comment . . . I mean, it's outrageous."