Nigeria Labour Congress on Monday faulted the reason given by the Minister of Interior, Abba Morro, for the Saturday's deaths of 20 applicants for the immigration job.
Morro had claimed that the applicants died in a stampede due to impatience and non-adherence to laid down guidelines.
In a statement on Monday titled, "Avoidable deaths of our youths", the NLC President, Abdulwaheed Omar said the minister's reason was "rather weak and untenable."
He wondered why 520,000 applicants were invited for screening for 4,556 spaces.
"To invite so much applicant for such few spaces, in all sense of administration was a call to anarchy and highly irresponsible of the immigration services," he said.
Omar urged the Federal Government to investigate the Nigerian Immigration Service and query the methods it adopted in the job recruitment.
He also asked the government to probe why the NIS collected "money from hard pressed applicants."
Describing this as a"rogue method of head hunting," Omar said the current scale of unemployment was a challenge which should get the government worried instead of its agencies extorting money from the unemployed.
He said, "We condemn in the strongest terms possible, the recruitment protocols adopted by the Immigration department. It is grossly unfair for the Immigration department to have invited several thousands of our youths to physically present themselves to compete to fill a miserly four thousand vacancies.
"Nothing but crass opportunism can explain this heartless scam. A more rational and discerning recruitment process, could easily have reduced the numbers by insisting on raising minimum standards. The Immigration Department willfully refused to employ this option in order to maximize the opportunity to bleed the applicants, each of whom, was asked to pay one thousand Naira.
"This corporate conduct fills us with disgust and we hereby call on government to provide greater protection for the unemployed, vulnerable as they may seem. The current environment leaves them open to serial abuses, and the deaths which have resulted from the Immigration exercise, are an extreme indication, of a widespread dysfunction, and crass incompetence of government agencies."
The NLC boss called on government to tackle unemployment with increased commitment, and to sanction those responsible for "these scandalous deaths."
"The specter of over 80,000 youths in a stadium in Abuja, assembled, not to watch an A-list football match, but rather, challenged by an epic hunger to have something to do, must break all hearts," he added.