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 claim the UK's departure from the EU 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.
Mrs Foster addressed the issue at an election event in Londonderry.
"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 powersharing immediately.
Talks to restore devolution have been parked over the General Election campaign and are due to resume in the second half of June.
Negotiations between the DUP and Sinn Fein are deadlocked on issues including legislative protections for Irish language speakers.
"The DUP is placing no obstacles in the way of a Stormont Executive returning," said Mrs Foster.
"No red lines. No pre-conditions. No demands. There is absolutely no need to wait until beyond the election. I would willingly re-establish government today.
"The public can decide for themselves whether the issues other parties are raising should be sufficient to stand in the way of good government for the province."
Mrs Foster, whose party campaigned for Leave in the referendum, told her audience in Derry that she was aware of people's concerns around Brexit.
"The United Kingdom's departure from the European Union inevitably brings with it an element of uncertainty," she said.
"As in my own constituency, I know those of you who live and work in the border area have particular issues that may affect you.
"Northern Ireland needs a stable Executive in order to achieve the best possible deal for Northern Ireland after the UK leaves the EU.
"Whichever way people voted in the referendum last June, and whatever concerns they may still have, we can all unite to ensure Northern Ireland's interests are promoted.
"The particular circumstances of Northern Ireland are well understood in Brussels, and working together sensibly we have the opportunity to secure a good outcome that delivers for everyone.
"Electing the strongest and most effective team of representatives at Westminster with the influence to make a difference, will also help."