As Environment Minister Phil Hogan refused to rule out a snap by-election to coincide with the May local and Euro polls, Fianna Fáil leader Micheál Martin set his sights on retaking Brian Lenihan’s old seat.
Labour rebel-turned-independent TD Mr Nulty was keeping a low profile after revelations he sent an inappropriate Facebook message to a 17-year-old girl.
Mr Nulty, 31, said he sent the messages while under the influence of alcohol.
One of messages asked the teenager: “Have you ever been spanked?” The Sunday World reported.
When the girl’s mother became aware of the contact, she approached the TD and he initially claimed his phone had been hacked, before admitting his guilt, it was reported.
The TD was also alleged to have sent inappropriate messages to female constituents, but gardaí said they have so far received no official complaints.
The TD was reported to have asked one woman to send him underwear, while he asked another to wear a skirt when visiting his office.
In a resignation statement issued just before the newspaper revelations emerged, Mr Nulty said: “I sent inappropriate messages via Facebook. This included inadvertently sending one to a 17-year-old woman.
“To the best of my knowledge, I have never met this woman and the message was sent while under the influence of alcohol,
“I apologise wholeheartedly to the woman involved and to her family. It was never my intention to upset anyone in this way but it was totally wrong.”
Mr Hogan said that new rules meant the by-election had to be held by the end of October, but would not be drawn on the seat being contested as early as May.
Fianna Fáil councillor David McGuinness finished a strong second in the October 2011 by-election which took Mr Nulty to the Dáil.
If the party retook the seat, it would be its only one in Dublin.