The information was gathered following a survey of the 158 Dáil representatives.
Four midlands TDs are among those who have a second job or income outside of the Dáil.
Laois TD and Justice Minister Charlie Flanagan, along with Longford-Westmeath deputies Robert Troy, Kevin 'Boxer' Moran and Willie Penrose, all responded to a survey of the 158 Dáil reps.
Minister Flanagan has a second income as a landlord, Fianna Fail's Robert Troy is also a postmaster and landlord, Labour TD Willie Penrose is a barrister, while OPW Minister Kevin Boxer Moran is Managing Director of a taxi company in Athlone.
The Irish Independent reports that less than half of TDs responded to their questions.
The issue of double jobbing is being discussed after it came to light ex Fine Gael deputy Dara Murphy claimed his full expenses, while also working in another job for the EU in Brussels.