Just over a third of the 123 parliamentary assistants appointed to assist TDs are actually based in Leinster House. The remainder work from TDs' constituencies.
Latest figures also show that there are now more than 400 non-civil service political staff on the payroll of the Oireachtas to help TDs and senators with their work, a ratio of nearly two staff to every politician in Leinster House.
An examination by The Irish Times of the names of parliamentary assistants, released under freedom of information legislation, shows that of the 123 parliamentary assistants, only 42 of them are listed in the Leinster House office directory.
The position of parliamentary assistant was created last year following a study by consultants Deloitte and Touche which found that TDs and senators had a much lower level of staff support than elected representatives in Britain and Europe.
When the posts were first suggested in 2004, it was envisaged that they would help TDs in writing speeches, researching issues and legislation, and liaising with the media.
However, by the time the scheme was implemented in early 2005, their remit had been expanded to include duties in their TDs' constituencies, such as dealing with representations and attending funerals. TDs had argued that this would give them more time to concentrate on parliamentary work.
It now emerges that two thirds of TDs have opted to base their parliamentary assistants in their constituencies as opposed to Leinster House, which is equipped with one of the best research libraries in the country.
Of the 42 parliamentary assistants listed as having offices in Leinster House, 30 are working for Dublin-based TDs.
The parliamentary assistants are paid between €37,000 and €45,000 a year, depending on seniority. A total of 115 of the 167 TDs in Leinster House have opted to have parliamentary assistants - there are 123 names on the list of assistants because of job sharing arrangements.
The remaining TDs have opted for a research grant and secretarial assistance of up to €35,000 instead of having a parliamentary assistant.
Fifteen of the assistants on the list are related to the TDs for whom they are working. They include Niall Collins, a Fianna Fáil candidate in the next general election who works for his father, Limerick West TD Michael Collins.
Fianna Fáil councillor Kevin O'Keeffe also works for his father, Cork TD Ned O'Keeffe.Fine Gael Mayo TD Michael Ring's assistant is his daughter Suzanne. Labour TD Joe Costello has his wife Emer as an assistant, while his party colleague Kathleen Lynch has her husband Bernard.
Nine county councillors are on the list of parliamentary assistants.
A number of TDs have opted to give the positions to long-standing secretarial assistants, as the parliamentary assistants are paid up to €10,000 more than Dáil secretaries.
The assistants were appointed through an interview process by the Houses of the Oireachtas Commission last year, with TDs forwarding the names of the people they would like to see employed to work for them. The assistants lose their posts when their TDs leave the Dáil. However, they have pension entitlements based on their years of service.
The appointment of the parliamentary assistants means that there are now more political staff than civil servants on the payroll of Leinster House.
According to the latest figures, there are 402 staff employed by parties, TDs and senators in Leinster House.
These include 242 secretarial assistants, 115 parliamentary assistants, 29 administrative assistants, 12 administrators and two chefs de cabinet. This compares with 375 civil servants who are involved in operating the Houses of the Oireachtas, including ushers, clerks, librarians and maintenance staff.
The Dáil currently costs more than €100 million a year to run. TDs, senators and MEPs receive just over €21 million a year in salaries. Secretarial assistance to the politicians costs €15 million. They receive a further €13 million in travel and other expenses.