SMART cards that allow students to borrow library books, enter secure areas and pay for goods without cash could also be used to track their movements.
A study by Nottingham Trent University of how smart cards are used in the United States found the technology exists to monitor every part of students' daily lives.
Peter Le Bosquet, general manager of Nottingham Trent Student Union, who helped compile the report, said: "You could find out which lectures they go to, when they use the library, what book they read, when they have a hamburger, when they visit a shop and what they buy. It has significant implications for both students and universities."
He said it was vital for all parties to discuss the implications before introducing the cards.
In this country, smart cards are only used at the universities of York, Exeter, Nottingham and Sheffield Hallam, but many more institutions are planning to introduce them in the next few years.
Usually bearing a student's photograph and a bar code, they can be used to pay for telephone calls, photocopies and goods around the campus. Students at Exeter can use the cards to access and update information held about them by the university and to register at the beginning of the academic year.
Some cards also allow access to restricted areas and double as ID. This makes it possible for university authorities to find out who is inside a building at any one time, which could be useful in an emergency. The sheer weight of data, as well as ethical problems, means this information is usually kept for only 24 hours.
But Glyn Stanfield, a partner at education lawyers Mills and Reeve, said unless they were used carefully smart cards could bring radical changes to universities. "They could be used to show which lectures students attend, which libraries they use and when," he said. "They are also a potential source of information for anyone making research grants."
Students complaining about poor grades could find themselves presented with evidence that they had rarely attended lectures or read any books, he said. Research councils could demand more evidence of value for money.
At some overseas universities, such as Bar-Ilan University in Israel and several in the United States, the cards already record students' personal details, including grades achieved and books borrowed from the library.
But Keith Woods, director of management services at the University of Exeter, said use of the cards had been agreed with staff and students and the information stored on them would be released only in the event of a serious incident under police investigation.
A spokesman for the University of York said data from the cards could eventually be used to monitor students' buying patterns but the university would examine students as a general group rather than individuals.
Finance officers at York are investigating the advantages of smart cards if Britain joins the European Monetary Union. Graham Gilbert, York's director of finance, said they would provide the ideal way of running two currencies at the same time.