The Union of Students in Ireland has hit out at some universities for hiring debt collectors to chase down student fees.

University College Dublin is following in the footsteps of the University of Limerick, who have already used a debt collecting agency, according to a report in the Irish Independent.

Colleges are under increasing financial pressure because of funding cuts, but the President of the Students Union of Ireland John Logue said some students simply could not pay.

"I can appreciate those universtities trying to recover the money, but there is a point where (payment) is just not going to happen for several families or students," he said.

"Debt collection must be the last resort (and) I'm not convinced that it actually is (for these colleges)."