Students have reacted angrily to Education Minister Noel Dempsey's comments that he may reintroduce third-level fees.
A group of around 50 students protested as Junior Minister, Brian Lenihan, arrived to open a new facility at University College Dublin this morning.
They blocked his entry into the building and banged on the windows as he tried to speak.
The Union of Students in Ireland has also criticised the proposal.
USI President, Colm Jordan, said the Minister should come off the fence on the issue and he said parents would simply not be able to pay college fees of €4-5000 a year on top of all the other costs associated with going to college.
Mr Jordan urged the Minister to think long and hard before reintroducing fees.
Earlier Trinity College students union said that any plans for the reintroduction of third level fees would be a disaster for thousands of students.
TCD students' union president, Will Priestly, said that Mr Dempsey had not done much to help the disadvantaged in our education system.
The National Parents Council, Post-Primary has also criticised the Minister. The Council said middle-income families would be worst affected.