The Labour Party has described Tom Parlon's move to the Construction Industry Federation as "unethical".
The party has claimed that there could be a serious conflict of interest, given that Mr Parlon has just left the position of Minister in charge of the Office of Public Works.
Deputy Labour Leader Liz McManus has said he should be forced to take a year off before accepting such a high-profile role in the private sector.
This move by Tom Parlon casts further doubt over the future of the Progressive Democrats in Irish politics.
The party has just two Dáil seats following the general election and Mary Harney has said she does not want the position of party leader again.