Collective government in Northern Ireland will be almost impossible in the future as voting habits evolve, according to former Taoiseach Bertie Ahern.
The one-time Fianna Fail leader also said his party and Fine Gael will likely remain close partners in the coming years, and may merge together as a single organisation at some time in the future.
Currently, Stormont's Executive is made up of five parties in a mandatory coalition, where major parties cannot be excluded from the power-sharing government.
But Mr Ahern said he could see a day when it could become a voluntary coalition.
"I do think in the future that will probably change," he told Radio Ulster's Talkback, but added: "I do not think this is the time."
"In a democracy it is odd to not have the to and fro of... politics, opposition."
He predicted a time - as voting habits continue to change, with younger people gravitating towards other parties, including Green and those on the Left - when "it will become almost impossible to have a collective leadership".
"I think it would be more normal and I think you'll find in time that will happen," he said.
On the future of the political system in the Republic, Mr Ahern said a coalition government of Fianna Fail and Fine Gael was not something he would have foreseen years ago.
But over the last 10 years "more and more you could see the centralised policies of Fianna Fail and Fine Gael moving closer together, mainly on economic issues, though not necessarily on social issues".
The public has watched Fianna Fail "propping up Fine Gael", while the strong performance of Sinn Fein and Independents in the last election has further changed the political landscape, he said.
Mr Ahern said "we are now probably into the era of three big parties" instead of the traditional two.
If the new government works and does a "good job" in challenging times, with the economic effect of Covid-19 and Brexit, then the former Taoiseach does see the two parties continuing in partnership.
On a new party evolving out of the two merging, Mr Ahern said: "I think it is possible, though not in the foreseeable future."
Mr Ahern recalled his relationship with former DUP First Minister Paisley, including their first meeting on the site of the Battle of the Boyne in 2007, and a ribbon-cutting ceremony for the opening of a visitor and heritage centre the following year.
"We had that great day at the Battle of the Boyne... for several years I wanted to turn that site into more than just fields... move history on, 1690 was a long time ago," he said.
He added: "I built up that relationship with Ian and Eileen and I had a great regard for him. It was a sad day when we lost him."