A number of Fianna Fáil TDs are now embroiled in the issue.
An Offaly TD is denying ever asking a colleague to vote for him when he's not in the Dáil chamber.
Fianna Fáil's Barry Cowen was recorded as taking part in a vote earlier this year, despite being away from his seat.
This controversy erupted when it emerged Fianna Fáil TD Niall Collins had voted on behalf of his party colleague Timmy Dooley six times.
They've since been suspended from the frontbench, while the Ceann Comhairle carries out an investigation into the matter.
Offaly TD Barry Cowen is now the latest to become involved.
In a statement, Deputy Cowen says he's never asked a colleague to vote for me when I was not in the chamber.
He says there's a "known practice of members who are in the House asking colleagues to press the voting button if they are away from their seats in other parts of the chamber".
He believes people have "trust and integrity in the voting system", and has been welcoming the Ceann Comhairle investigation.
He hopes the reports recommendations will tighten voting practices to avoid any any future discrepancies.