David Norris is now just four names short of a formal nomination to run for the Presidency.
His Seanad colleague Mary Ann O'Brien is the latest to nominate him, bringing to 16 the numbers who have signed his nomination form.
Senator Norris is continuing discussions with a number of other Independent TDs and Senators in a bid to get the 20 signatures required.
Meanwhile, Deputy Mattie McGrath said he was committed to supporting Dana Rosemary Scallon in her bid to get on the ballot paper once more.
The Tipperary South TD said that if Scallon did not require his vote, he was not ruling out backing Senator Norris, because democracy would be stymied by his exclusion.