Among the 57 questions employees are asked in the "Integrity Questionnaire" are whether the employee has ever "solicited the service of a prostitute" and how much alcohol the worker consumes in a week.
The survey asks whether the employee gambles or plays lotteries and whether they have ever engaged in domestic violence, the Canadian Broadcasting Corp. reported.
Jason McMichael, an official with the Customs and Immigration Union, told the broadcaster members were being encouraged not to complete the form.
"The questions are exceptionally intrusive," he said. "And to be quite honest, some of the questions are to the point of being ridiculous."
The CBC noted the Canadian Human Rights Commission guide to employment screening specifically says to avoid asking questions about drinking, drug use and whether the person is receiving counseling or therapy.
The CBSA website is also ambiguous about the survey, calling it mandatory at one point and voluntary with consequences at another.
"If an individual refuses to provide answers to any or all of the questions contained in the integrity questionnaire, this may result in disqualification and may be interpreted as a withdrawal from the security screening process," the agency says.