The Rev Ian Paisley's Democratic Unionists will consider a pact with the rival Ulster Unionists at the next general election.
Deputy leader Peter Robinson, the East Belfast MP confirmed he had invited Sir Reg Empey's party to take part in wide ranging discussions aimed at maximising the unionist vote.
Even though authoritative sources close to the Prime Minister Gordon Brown have almost certainly ruled out a snap poll this year, Mr Robinson said his party's preparations for an election were well under way, and they would face it with renewed confidence and vigour.
As his party's director of elections, he said: "As part of our election preparations we have invited the Ulster Unionist Party to participate in wide ranging discussions around maximising the unionist vote in future elections.
"The Assembly election results demonstrated that greater co-operation between unionist candidates could have increased the total number of unionists returned to the Assembly.
"There are a number of areas where discussions could yield substantial benefits for unionism. Turnout in unionist areas and vote management in marginal seats are amongst the issues which we hope to address."
Two of the constituencies likely to be at the centre of any negotiations will be south Belfast and Fermanagh-south Tyrone which both sides believe could be won by a single unionist candidate.
Mr Robinson added: "It is important that we take steps to safeguard and expand the unionist vote and ensure that unionists enter the Westminster election in the strongest possible position in order to maximise the unionist vote and increase the number of seats held."