TDs from across the political spectrum have admitted to voting for colleagues who were present in the Dáil chamber but who were not in their designated seats.

Deputies including Fine Gael’s Hildegarde Naughten, Peter Burke and Fergus O’Dowd, Fianna Fáil’s Anne Rabbitte and James Lawless, as well as Sinn Féin’s Louise O’Reilly, said they may have pressed a colleague’s voting button but only when they were actually in the chamber.

The controversy over Dáil voting deepened as Ministers also disclosed they voted for colleagues, although no further TDs have come forward to say they voted for absent representatives.

The two senior TDs stood down from the party’s frontbench at the request of Fianna Fáil leader Micheál Martin, pending the outcome of an investigation into alleged voting irregularities by Ceann Comhairle Sean O Fearghaíl.

Separately, Fianna Fáil’s Lisa Chambers said she sat in her colleague and party deputy leader Dara Calleary’s seat last Thursday and voted mistakenly for one vote before moving to her own seat for the same vote as soon as she realised.

Minister for Justice Charlie Flanagan has written to the Ceann Comhairle over what he has described as the “illegal act” of a Fianna Fáil frontbencher voting for a colleague absent from the Dáil.

Mr Flanagan declined to apologise for having voted for other colleagues himself while in the chamber.

Minister for Communications Richard Bruton said TDs casting ballots for each other while are both in the chamber was “common practice”.

“But what has gone wrong here is that people not in the chamber at all voted.”