The Students' Union at University College Dublin says it has suspended the sale of student Leap Cards because of concerns over data protection.
The cards, which offer student discounts for transport, are sold by students' unions around the country.
However, UCD Student Union President Barry Murphy says they have discovered that students' personal information is in danger of being misused.
Mr Murphy said: "The personal information is viewable by way too many people and means that data can be taken and sold to third-party companies.
"That student could end up being spammed meaning there could be identity tests, if someone took a shine to how they look they could find out where they live and they can also look at a picture of them and they could end up stalking them.
"So, we just think it was wholly inappropriate and we are looking forward to working with the NTA to resolve it."