Senator David Norris has refused to remove his Yes badge in Leinster House.
Mr Norris was asked by the Superintendent of the House to take the emblem off, but the Independent Senator refused.
Speaking to The Irish Times, Mr Norris, who wore the badge – which favours a Yes vote in the upcoming same-sex marriage referendm – around the houses of the Oireachtas, said: "The rules state you cannot wear party political branding. This is not party political. I am an Independent and I will not remove it."
Mr Norris said he would not take any objection to a member or a visitor wearing a No badge even if he doesn’t agree with their stance.
Fine Gael TD Jerry Buttimer is also refusing to take off his emblem. He said if there was consistency and unity in the approach taken, he would follow the rules.
“I adhere to the dress code and the behaviour in the house and if there is going to enforcement, it must apply across the political divide and that is the way it should be,” said Mr Buttimer. “I will be wearing my Yes pin.”
Ushers were told last week to remind people of the long-standing tradition when they entered Leinster House.
A spokesman for the Houses of the Oireachtas confirmed “members, staff and visitors asked to remove emblems”, to comply with rules.
“Members, staff and visitors continue to cooperate on the longstanding protocol around emblems of a party political nature in the precincts of Leinster House,” he added.
“From time to time, members and staff inadvertently display such emblems – for instance, on return from events outside the House. They invariably cooperate with the Leinster House ushers when reminded of this protocol.
“As there has never been wilful and persistent breaching of this protocol, the question of sanction is in the hypothetical and does not arise.”