The DUP will not participate in today's first meeting of the North-South Ministerial Council in Armagh, but one of the party's ministers has said he could envisage co-operation with the Republic in areas of mutual interest.
The Minister of Regional Development, Mr Peter Robinson, said the DUP saw the North-South body as part of a "nationalist agenda".
"I will not be there. We see this North-South structure as part of a political purpose, part of the nationalist agenda to bring about a united Ireland. As far as we are concerned, we will not be aiding the political process towards a united Ireland," he told BBC Radio Ulster. Mr Robinson did not exclude the possibility of working with his counterpart in Dublin on matters which benefited people on both sides of the Border.
"We believe there should be co-operation with the Irish Republic on matters which are to the mutual benefit of people in Northern Ireland and those in the Irish Republic. If I see an area in which it would be helpful to the people of Northern Ireland if I had better consultation with my counterpart in the Irish Republic, then I will do it."
Asked why his party was prepared to sit with Sinn Fein on local councils and Assembly committees but not on the Executive, he said: "In a council, the Assembly or on a committee, we are there to oppose everything that Sinn Fein stands for. In a government, we would be in a position where we would have to be in partnership with Sinn Fein."
While he was prepared to speak to civil servants from the Department of Education, he was unwilling to have any personal contact with the Minister, Mr Martin McGuinness, Mr Robinson said.