One of Sinn Féin's most senior politicians at Stormont, Minister for the Economy Conor Murphy, is seeking to find a new political home and will stand for election to the Seanad next month.
A Stormont Assembly member for Newry and Armagh for 26 years he has been Sinn Féin's senior negotiator in discussions with the Irish and British governments and other parties for many years.
He has also held the portfolios of regional development and finance.
If elected he will resign from the Assembly.
Mr Murphy will contest the Seanad election in the industrial and commercial panel.
In a statement, Sinn Féin leader Mary Lou McDonald said his candidacy underscores her party's commitment to representing the entire island of Ireland, promoting the All-Ireland economy and advancing the Irish unity debate in the Oireachtas.
"With over thirty years of service as a Councillor, MP, and Assembly Member for Newry/Armagh, Conor brings unparalleled political and ministerial experience holding senior positions within the party and the northern Executive," she added.
"He brings a huge wealth of experience as the party now continues to build our All-Ireland political project. He has been a consistent champion for the All-Ireland economy, infrastructure and connectivity representing a border constituency."
Ms McDonald said Mr Murphy will continue serving as a member of the Northern Ireland Assembly and economy minister until the Seanad election concludes, adding that they will asses next steps after the election.
Speaking to RTÉ News, Mr Murphy said he believed it was the perfect time for him to seek election to the Oireachtas because of the growing debate about possible unification.
"This is about the big picture politics, the constitutional debate, it's a level it's never been before," he said.
"All parties in the south in their election manifestos committed to much more intensive work in terms of the debate, which will inevitably lead to unity referendums.
"To be able to be part of that preparation work in the Oireachtas with our own team, they're a strong team working there, but also across other parties given the experience I have in relation to the various portfolios I've held here but particularly around finance and the economy, to bring that level of experience and know-how and contacts I have.
"I've worked with every Irish government, people in it, both elected and non-elected since the Good Friday Agreement, to bring that, I think it's the perfect time for me to go and make a contribution in terms of the constitutional debate."
Mr Murphy rejected the suggestion that his move was part of a strategy by Sinn Féin to bolster its political team in the Republic after what many regarded as a disappointing General Election result.
"It's very much about the constitutional debate, it's about the role I can play there," he said.
Sinn Féin's handling of the resignation of its former leader in the Seanad, Niall Ó Donnghaile, who sent inappropriate messages to a teenager, could feature in the election campaign and any debates.
Ms McDonald had to apologise for its treatment of the victim and how it communicated the resignation.
"Listen, you expect anything in politics, politics can be a dirty game as well as anything else but I will be going down there on a very positive note," Mr Murphy said.
"I have no doubt that others will want to raise whatever questions they wish to raise, but I mean you can't be deflected by all these things in politics.
"If you have a plan to move forward, an opportunity as I now have to make a contribution to what is the thing that motivated me becoming involved in politics in the first place is constituitonal change on this issue. I have an opportunity make a contribution and I'll be determined to do that."
