Sinn Féin leader Mary Lou McDonald has said that Brexit presents a "constitutional earthquake" for this country and is a "game-changer" for the future of the island of Ireland.
Ms McDonald also said that re-joining the Commonwealth is "a bad idea" but supporters of such a plan should be allowed to debate it openly and that Fine Gael should state clearly if they are in favour.
Speaking on WLR FM on Monday morning during a visit to Waterford, the Sinn Féin leader criticised other parties for their approach to the issue of constitutional change.
"The other political parties and leaders have their head in the sand. They say, 'let's not talk about the fact that constitutional change is coming, that the issue of the border now with Brexit looms larger than ever before'. They seem to think that they can look the other way and hope that all of this will go away.
"I'm telling you that that is not the case, I am saying very clearly that Brexit at this time is a constitutional earthquake, it's a gamechanger. It is not a transient thing, it is for keeps. We have a huge job of work to do, and I'm very conscious of it as a leader of a party that represents northern nationalism, to build bridges, to create a new society."
Politicians such as herself have a "duty of candour" to present their views honestly in that debate and to be "very respectful" of others with different opinions, she told Déise Today presenter Damien Tiernan.
Following DUP MP Jeffrey Donaldson's call at the Fine Gael Ard Fheis at the weekend for Ireland to re-join the Commonwealth, which was greeted by applause from some delegates, Mary Lou McDonald said "it demonstrates how utterly out of touch Leo Varadkar and Fine Gael are, that this is the big story coming from their Ard Fheis at a time when people here in Waterford and around the country are concerned about their health service, they're concerned about housing... That's the first thing that struck me, this is their priority. How crazy."
She added: "We are now at a time that we need to deal with the issue of constitutional change on our island. I think it is really, really important that we have an open, inclusive, honest debate and conversation around what all of that means.
"I do not advocate re-entering the Commonwealth. I don't think it's a good idea. I think it's a bad idea. But I also have to accept that in an open and full debate, you have to allow others who believe that it is a good thing or a necessary thing to come forward and make their case for it.
"If Fine Gael are actually in touch, which I have my doubts on, but if they observe the bigger politics of what's happening in Ireland they would have to understand that their ambition to be back in the Commonwealth could only be debated, even, in the context of Irish unity. But to each their own.
She said she doesn't advocate joining the Commonwealth or "going backwards" following the history of imperialism and the "huge damage" done to all of the people on this island.
"The nature of debate and deliberation is that you can be informed, you can be persuaded and, critically in terms of building our new Ireland, our united Ireland, we can see where the other party is coming from, where the other people are coming from, and we can make the necessary strategic compromises and accommodation so that every person who calls this island home can be comfortable living in the new Ireland."