The DUP is urging its supporters to give their second and third preference votes to the UUP and UKIP in order of their choice.
The call, by the party leader Peter Robinson, follows a proposal by Mike Nesbitt, his UUP opposite number, for a unionist voting pact in the European and local government elections on May 22.
In a keynote address to his party's spring conference in Newcastle, Mr Robinson said: "Within unionism, division costs. Wasted votes, lost seats, lost power and lost influence. And that's to say nothing of the enormous amount of time and energy that's taken up by unionist parties arguing – often over points of detail rather than matters of substance.
"On the nationalist side there are two simple choices, whereas unionism is split and splintered over more than half a dozen options."
Speaking to the Belfast Telegraph afterwards, he made it clear that he was only advising voting transfers to the UUP and UKIP. He did not include parities like the hardline Traditional Unionist Voice, headed by former DUP Euro MP Jim Allister, or NI21, the moderate group led by Basil McCrea.
"In the context of a European election, in the context of any election, we are far ahead of any of the other unionist parties. Coming behind us, the UUP and UKIP are the two main parties likely to pick up votes. Jim Allister, certainly in the context of local government, won't be doing too much. People squander and weaken their vote if they go outside the main parties who are standing," Mr Robinson stated.
"I am not giving the order. I might at a later stage but I doubt it."
He stated that no unionist should vote for the centrist Alliance Party which he said could no longer be considered a "small 'u' unionist party".