OTTAWA - The Defence Department lifted a media gag order Friday on suppliers interested in providing new radar equipment to military airfields across Canada.

But it's only one of a growing number of contracts in which people who want to do business with federal or provincial governments must agree not to talk to the reporters.

The department issued a letter of interest last Monday, asking suppliers for information on what kind of new radar systems are available to replace aging installations at Trenton, Ont., Cold Lake, Alta. and other bases.

The documents stated that "no information or statement pertaining to this project shall be released to the press or other news media except by written permission from the Department of National Defence".

The secrecy clause soon received media attention, and by Friday, it was pulled.

"Public Works decided that this statement was not necessary," said Jacques Gagnon, spokesman for the minister of public works.

"This statement...has been a feature of military contracting preceding our time in office, and is used rarely in order to maintain confidentiality over sensitive purchases."

A review of past government proposals by The Canadian Press shows the practice is not uncommon. The same gag order, worded exactly the same way, has been used at least five times since November 2006 for Defence Department purchases ranging from computer software to warship machinery.

The practice has raised concerns with Democracy Watch, an Ottawa-based citizen advocacy group.

"That is, I think, not only undemocratic and overly secretive but also unconstitutional, given that people have a right to freedom of expression in Canada and the public has a right to know what is happening with government spending," said group spokesman Duff Conacher.

It's not only defence matters that governments want to keep a lid on. The Manitoba government often imposes gag orders for everyday supplies that continue long after the contract is over.

A tender issued Friday for diapers, baby wipes and other items for provincial hospitals stresses the need to keep the diaper details under wraps in perpetuity.

"Neither the bidder nor its suppliers-vendors, employees or consultants shall make any public statement relating to the existence or performance of the purchase order-contract without the prior written consent of the province of Manitoba, which shall not be unreasonably withheld," the tender says.

"The provision of this condition shall apply during the extension of a purchase order-contract and indefinitely after its expiry or termination."

The government says the clause is aimed at preventing contractors from using the province for testimonial advertising, although the clause also covers news interviews .

"If we didn't have that clause in, that vendor could then take a full-page ad out and say, 'Look, people, the government of Manitoba says my product is the best'," said Tracey Danowski, the province's assistant deputy minister of supply and services.

"If (reporters) wanted to talk to them and we had a compelling reason why we should not allow that, we would tell the vendor they can't do it. But we're also saying the province of Manitoba is not going to unreasonably withhold that information."

The requirement for communications control is a sign of a changing mindset among politicians and bureaucrats, says an analyst.

"I think it does say something about the emphasis these days, particularly in Ottawa, on control over information and avoidance of revelations or disclosures, and a desire to avoid any negative news arising," said Paul Thomas, a long-time political science professor at the University of Manitoba.

"That starts at the political level . . . and then it flows through into the administrative culture. Public servants know the government is quite secretive and doesn't want information released, and they're not going to be caught doing that if they can avoid it."