Independent presidential candidate David Norris received a disability payment for 16 years while out of work as a Trinity College lecturer -- even though he was a "full-time" senator for the entire period.
He also refused to say what his disability is.
He said the payment was around a quarter of his annual salary, but said he "wasn't getting anything like they get now".
The 67-year-old Joycean scholar worked as a tutor and lecturer in Trinity between 1968 and 1994, when he took the disability payment and stopped working in the college.
The payment began in 1994 and ended in July of last year, when he reached pension age. He has since received a pension from the college, worth around €2,500 a month.
Mr Norris, who took part in last night's TV3 debate with his six Aras rivals, also receives a senator's salary of €61,073.
He also said he spent his annual leader's allowance -- the €23,383 Independent senators receive in unvouched expenses every year -- on his Seanad work.
Mr Norris, who was first elected as a senator for Trinity in 1987 and has been returned at every election since, focused on his Seanad career after 1994. However, he would not say what the disability was, and insisted it did not stand in his way of being president, insisting he is in "perfect health".
"And if you look at my Seanad record you see that. I hope we're not going down the medical route of all this but I will do any medical test you want. I just think this is getting daft. It shows how open I am, my life is an open book."
But he asked not to go into the disability payment, saying there "was a whole story about that".