Tánaiste Leo Varadkar has said he believes a united Ireland can happen during his lifetime.
He also announced Fine Gael intends to set up a political branch in Northern Ireland.
In a speech opening his party's 80th Ard Fheis, he appealed for neither Brussels or London to take unilateral action when it comes to the Northern Ireland Protocol.
And Mr Varadkar said a united Ireland is something that should be aimed for.
"I believe in the unification of our island, and I believe it can happen in my lifetime.
"It means the unification of the people of our island, as well as the territory of Ireland, and is a legitimate political aspiration.
"It's in our Constitution, and is provided for in the Good Friday Agreement."
Mr Varadkar also said preparations should be made for the holding of a border poll at some point in the future.
"The views of unionists must be acknowledged, understood and respected - but no one group can have a veto on Ireland's future.
"We should be proud to say that unification is something we aspire to.
"It should be part of our mission as a party to work towards it, and we can do so in many ways.
"We have to be willing to consider what we'd be willing to change: new titles, shared symbols, how devolution in Northern Ireland would fit into the new arrangements.
"A new Senate, perhaps, designed to strengthen the representation of all minorities, the role and status of all of our languages and a new and closer relationship with the United Kingdom".
Earlier this year a poll found that 67% of people in the Republic were in favour of a united Ireland.
However, it suggested more people in the North want to stay in the UK than leave - with just 35% backing a merger with the 26 counties, compared to 43% against.
The poll of 2,250 people across the island showed only one in five voters across the 32 counties on the island would be prepared to pay more tax to fund a united Ireland.
In the Republic, only 22% of people said they would be happy to pay more tax - compared to 54% who would not.
In Northern Ireland, meanwhile, 63% said they would not pay a higher tax.
While former Taoiseach Bertie Ahern has previously said that any border poll should be held to coincide with the 30th anniversary of the Good Friday Agreement, in 2028.
Speaking to Newstalk in February, he said two elements are essential before any ballot.
"Two things have to happen: one is that we had to have institutions under the Good Friday Agreement that were stable for a prolonged period - we haven't had that ever since the agreement was signed 23 years ago almost now.
"And the second point I made at that stage [was] that the preparatory work that made sense of all of this, which has really only commenced.
"There's the Shared Island Unit, which is something I support that the Taoiseach has done within his department.
"But there's a whole lot of other academic work going on.
"Both of those things have to happen.
"And what I said at that stage, and I still say, that any idea of a vote that was seen in the Good Friday Agreement should be probably on the 30th anniversary of the Good Friday Agreement - which is the end of the decade."
Additional reporting: Jack Quann
