Students were last night pinning their hopes of stopping the reintroduction of college fees on legal difficulties which may be encountered by the Minister for Education, Mr Dempsey.
The Union of Students in Ireland (USI) said it believed Mr Dempsey would face major legal obstacles if he proceeded with plans to reintroduce fees based on the income of a student's parents.
USI president Mr Colm Jordan said the union's advice was that any scheme which assessed the parental income of students over the age of 18 could run into serious problems.
He said the chances of a student taking a test case, either through the courts or via the Equality Authority, were high.
The reintroduction of fees could be legally fraught, legal experts said.
An academic from DIT's law school, Ms Ruth Cannon, said there could be difficulties if parents refused to pay for their child's third-level education. She said some parents might take this course simply so their child would then qualify for grant assistance.
Mr Jordan claimed problems could arise under equality legislation. He said it might be regarded as unjust and discriminatory to have, on the one hand, an 18-year-old adult's assessment based on parental income, while a mature student of 23 could be assessed on their own income.
However, Dr Tom Collins, director of the Dundalk Institute of Technology, said it was right to reassess the free fees initiative.
"I believe that free third-level fees are socially regressive, constituting a transfer of scarce national resources to the better off. There is a strong case for reassessing the impact of this scheme," he said.
The continuing debate about the issue came after a dramatic day at the Department of Education's offices at Marlborough Street in Dublin. A group of seven students from USI spent most of the day barricaded into the Minister's conference room in a protest about reintroducing fees.
Their protest was brought to an end at about 6.20 p.m. when gardaí used a battering ram to force the door open and expel the students. The students' names were taken, and they were allowed to join their fellow students gathered outside. According to USI, gardaí told the students they would be charged at a later date.
Throughout the day students from several Dublin third-level colleges converged on the Department and at one stage the crowd numbered up to 300. Mr Jordan addressed them last night before they dispersed.
"We are not taking this drastic action for the sake of a revolution, it is the only legitimate action we can take, as we cannot withdraw labour or remove investment. If third-level fees were to be reintroduced, there would be dire consequences for Irish education," he told the crowd.
Meanwhile, the Fine Gael spokeswoman on education, Ms Olwyn Enright, called on Mr Dempsey to clarify immediately whether or not he intended to target existing third-level students with his proposed reintroduction of college fees.
Students who were already within the system were extremely worried about the possible reintroduction of tuition fees, she said.