A border poll would destabilise Northern Ireland at a time when stability is required, Democratic Unionist leader Arlene Foster has warned.
The former first minister expressed confidence the pro-Union position would be "resoundingly endorsed" in any referendum on Irish unification, but she said the exercise would have a negative impact on the political and economic landscape.
The issue of a potential future vote on a united Ireland has gained increased prominence as the debate around Brexit has evolved.
Republicans say the UK's departure from the European Union is a gamechanger, with reunification now providing a pathway for Northern Ireland to remain inside the EU.
Unionists insist the pro-Remain vote in the region (56% to 44%) cannot be interpreted as a swing in favour of Irish unity.
Ms Foster addressed the issue at an election event in Derry.
"There has been some talk about the prospects of a united Ireland or a border poll," she said.
"Whatever anyone's reservations about exiting the EU, our Union with Great Britain will continue to be massively and fundamentally in Northern Ireland's interests.
"I have absolute confidence that any border poll would see a resounding endorsement of the pro-Union position.
"However I also recognise the destabilising effect an unnecessary campaign of that nature could have on business and politics here.
"Northern Ireland needs a period of stability, not instability."
On the current Stormont crisis, which has left the region without a functioning government for two months, the DUP leader reiterated her willingness to re-enter power-sharing immediately.
Talks to restore devolution have been parked over the British general election campaign and are due to resume in the second half of June.
Negotiations between the DUP and Sinn Féin are deadlocked on issues including legislative protections for Irish language speakers.
