The personal driver of former Ceann Comhairle Sean Barrett reportedly claimed over €11,000 in overnight expenses last year.
The Sunday Times has reported that Dominic Hearn, a former garda, was eligible for a €125 untaxed payment for each day worked, as he was not resident in Dublin.
Mr Barrett's commute, from Killiney to Leinster House, is around 15km.
In the year ending January 2016, Mr Hearn claimed €11,301.12 in overnight expenses, which were approved by Mr Barrett.