OTTAWA - The Conservative government is facing criticism for using the personal income-tax information of more than 500 sitting federal judges during salary negotiations.

The lawyer who acted as counsel for the judges says the tactic may have violated their privacy and threatens the independence of the judiciary.

And a leading criminal defence lawyer agrees the move may have undermined the principle of an independent judiciary and shows the Conservative government has a "hostile'' attitude to judges primarily appointed by Liberal governments.

Pierre Bienvenu, a high-profile Montreal lawyer who has represented the Canadian Judicial Council and the Canadian Association of Superior Court Judges, said judges were "astounded'' to learn about the gathering of their past tax filings.

"It has implications for judicial independence because what you end up with is a form of profiling of sitting judges, at least a financial profiling of sitting judges, prior to their appointment,'' Bienvenu said in an interview.

The Judicial Compensation and Benefits Commission recently submitted a report to the government calling for an increase in the salaries of more than 1,000 federally appointed judges to a minimum of $304,000 annually by April 1, 2011, from their current minimum of $260,000.

The commission's recommendation, which the government must accept or reject by the end of November, is significantly nearer the 2011 salary of $307,000 sought by the judges and well above the roughly $287,000 the government offered.

To buttress its position that salaries for federal judges are generally higher than the income they earned as lawyers in private and public practice, the Justice Department took the unprecedented step of giving the Canada Revenue Agency a list of the names of 627 judges the federal cabinet appointed to the bench between 1995 and 2007.

The agency was able to match 567 of those judges to their tax records as lawyers, and provided the Justice Department with an aggregated version of the information, with no names attached. A consultant used the data to calculate what the department claimed was an indication of the average increases in salaries and benefits lawyers received after they became judges.

The consultant's conclusions were vociferously challenged by Bienvenu and the judges' data expert.

In letters and submissions during the final stages of the salary deliberations, prominent lawyers the Justice Department retained to settle the conflict argued it was impossible to link the aggregated version of the tax data with the identities of judges whose income was scrutinized.

"The government, outside of CRA itself, and in particular the Department of Justice for purposes of this commission, had no access to the underlying data (the income tax returns),'' wrote Neil Finkelstein and Catherine Began Flood.

They acknowledged access that could identify taxpayers is "prohibited by law.'' The two lawyers, and assistant deputy attorney general Donald Rennie, argued CRA routinely provides anonymous information about professional groups or occupations of taxpayers on an aggregated basis.

Bienvenu said in an early letter to Rennie that the reaction of the judges was more than just "incomprehension'' at the fact the government would hand over names to the Canada Revenue Agency.

"There is also the reality that the party handing over the list to CRA is the government itself, and that CRA is a state organ that is part of the government and that has coercive powers to collect the data now being sought by the government,'' he wrote.

A spokesperson for the revenue agency confirmed it will release aggregated details of tax filings for names of individuals, but only if it is "convinced'' the number of individuals and the dispersion of income levels is broad enough that individual taxpayers cannot be identified.

A spokesperson for Privacy Commissioner Jennifer Stoddart said no complaints were lodged with her office over the intrusion into tax records, and that according to the information available publicly it appears the Privacy Act was not violated.

New Democrat MP Joe Comartin, however, said Stoddart should investigate the affair.

He said the government position that it obtained anonymous tax information is irrelevant, considering it was clear the files belonged to sitting federal judges. The main purpose of the independent commission system, established in 1999, was to take government's ability to pressure the judiciary out of the formula for establishing salaries, he argued.

"This whole battle for years about judicial compensation has been about independence,'' Comartin said.

"We've got to compensate them appropriately, without intimidation, so that they can do their jobs independent of the government.''

Frank Addario, president of the Criminal Lawyers' Association, said the incident is "regrettable, unfortunate; it displays a really hostile attitude toward the judiciary'' and reflects an antagonistic approach Prime Minister Stephen Harper and other Conservatives have displayed toward the judiciary in the past.

At one point in the last election campaign, Harper tried to assuage voter concern about a possible majority Conservative government by saying Liberal-appointed judges and public servants would be able to keep the Tories in check.

The commission, chaired by prominent Toronto lawyer Sheila Block, noted the tax information showed nearly two-thirds of judges received substantial salary increases when they were named to the bench and others received lower salaries.

But it said the study was irrelevant because it "only served to confirm that some appointees earn less prior to appointment and some earned more.''

The commission added the analysis also failed to show whether judicial salaries deter outstanding candidates for the bench who are in the higher-income brackets of lawyers.

The three-member commission -- one member nominated by the judges, the other by the government and the third by the first two -- also dismissed government "economic and social priorities'' stemming from the Conservative elections platform that the Justice Department argued put a limit on money available for judicial salaries.

Former privy council president Paul Tellier was the commission member nominated by the judges, while the government nominated Wayne McCutcheon, a former deputy secretary to cabinet.