First Minister Peter Robinson says he wants to see the creation of a single unionist party in Northern Ireland.
The Democratic Unionist leader said his party is in contact with the Ulster Unionists about the future of the two main pro-Union groupings.
He said relations have improved and he urged the parties to work together on a campaign to defend the Union against the threat of Scottish independence.
Asked if he would like to see a single unionist party, he added: "Of course I would like to see that, but very often if you start putting that out, you start causing problems for other people. Let's just improve the relationship we have, build on that relationship, and who knows where it might lead."
But he also expressed hopes that closer co-operation could help deliver the unionist unity that existed at the foundation of the Northern Ireland state. He said political co-operation was in the interests of the whole unionist community.
"We are in a year when we are looking back to the centenary of the signing of the covenant and the cohesiveness that there was within the unionist community at that time," Mr Robinson told UTV.
"I would like to see that coming about again. I think you probably will have noted that over the last number of months, some of the heat that there has been in the exchanges between the DUP and the Ulster Unionists has now been removed and there is a much improved relationship. I hope we can build on that."
Meanwhile Mr Robinson, 63, confirmed he would lead the DUP into the European Parliamentary election in 2014 - but left a question mark over any further role in politics.
He said: "What I have said is that I simply do not determine when I exit politics on the basis of a date on the calendar. There are things that I would like to achieve, there are things that I think can be achieved. And as long as I feel that I am making progress in that direction and that I am the best person to drive towards those goals, then I will continue in post. I haven't decided when to pull the curtains down."
But he added: "I hope that I will be able to lead the Democratic Unionist Party during the course of the next election, which of course will be the European one." He made no comment on whether his leadership will, or will not, extend into the following Westminster or Assembly elections.