Such schools pressure students into taking courses by touting they are useful for job-hunting and by claiming that the students would be unable to find work otherwise, the center said.

The NCAC asked universities and colleges through the Education, Culture, Sports, Science and Technology Ministry to warn students to take precautions against this kind of solicitation.

Local consumer advice centers across Japan report that between fiscal 2004 and fiscal 2008 there has been a four-fold increase in the number of such cases they have been asked to advise on -- a total of 223 in fiscal 2008 -- and the number is expected to rise further in fiscal which began in April, it said.

In one case, a 21-year-old university student in Aichi Prefecture signed a contract for approximately 600,000 yen after being solicited on two occasions to enroll in an English conversation class since April.

The agent, who obtained the student's phone number from a questionnaire he responded to in April after attending a company recruitment orientation, initially invited him to hear "things useful for job-hunting."

After he hesitated to enroll in the class, the canvasser persuaded him by saying things like, "Make your own decision right now as a grownup" and "You can pay for it by working part-time," according to the center.

Such a contract can be cancelled under certain conditions, the center said, encouraging victims to seek advice at local consumer centers.