OTTAWA—The Liberal government is facing questions over why more than 200 federal civil servants involved in replacing Canada’s aging fighter jet fleet have been forced to swear not to discuss the project for the rest of their lives.

The permanent non-disclosure agreements were implemented in January but only revealed in records tabled in the House of Commons this week in response to a question from the opposition Conservatives.

National Defence says 235 officials were required to sign agreements as a reminder to employees of their obligations to keep secrets.

But two former military procurement chiefs, including one who oversaw the F-35 stealth fighter project for seven years, say they have never seen such a move and that existing security measures are already stringent.

Conservative defence critic James Bezan, who asked the question, alleges the Liberals want to keep officials from revealing that their plan to buy 18 Super Hornet jets is entirely politically motivated.

The government says it needs the Hornets to address an urgent shortage of warplanes until a competition to replace all 77 of Canada’s CF-18s can be finished — a process it says could take up to five years.

Critics say the air force has enough planes at the moment and the decision to buy Hornets now and punt a competition to later is part of a larger Liberal plan to avoid buying the controversial F-35 stealth fighter.