The DUP is considering supporting Sinn Fein’s campaign for a border poll, according to enterprise minister Arlene Foster.
She told BBC Radio Ulster’s Stephen Nolan Show she had held discussions with senior colleagues, including party leader Peter Robinson.
She said the feeling was a pro-union vote would consolidate Northern Ireland’s position within the UK.
Sinn Fein is pushing for a referendum on the union.
Last week, Mitchel McLauglin of Sinn Fein told the assembly: “People have the chance to change the constitutional position on this island.
“If it could happen tomorrow I would, but I will wait for a chance to do it democratically.”
Ms Foster told the BBC on Tuesday: “Sinn Fein are trying to cause instability in Northern Ireland.
“If we have the border poll then that instability goes away and in actual fact what we have is a very clear validation of the union and that’s something we’re looking at at the moment.
“So I’m saying to Mitchel McLaughlin and I’m saying to him very clearly, ‘We may just call your bluff on this one Mitchel, and be very careful what you wish for’.”
Previously, the DUP has said that a referendum on a united Ireland would be a “waste of money”.
A border poll was last held in Northern Ireland in March 1973. It was largely boycotted by nationalists.