Martin McGuinness says he will veto any attempt to form an opposition or establish a voluntary coalition at Stormont as it would be an attack on his party.
However, he is less worried over whether or not he becomes First Minister.
Mr McGuinness strongly defended the present all-party system of government, warning that the British Government should not intervene without the approval of all parties, including Sinn Fein.
He said: “People can make arguments around the size of the institutions and say that there are too many parties in government, but the only alternative I hear is a voluntary coalition.
“Whenever nationalists or republicans look at that terminology they see a ganging up by all of the other parties to get Sinn Fein.”
He claimed that the SDLP and UUP would dishonour their obligations under the Good Friday Agreement if they failed to take up ministries and entered opposition; but he conceded he was powerless to stop them.
“They are already an internal opposition,” he said. “The UUP and SDLP are in denial about the fact that they are not the biggest parties any more,” he said.
“I am now deputy First Minister and there is very bitter resentment amongst the SDLP about that change.
“Within the Ulster Unionists there are people who thought they had the divine right to be in this office (OFMDFM) but when they were here the institutions collapsed three times.”
“Peter Robinson and I have a relationship where I see him almost every day and we have conversations, but before that I was part of an administration where Seamus Mallon (SDLP) and David Trimble (UUP) hardly spoke to each other.”
Asked whether he would consider it a major boost if he were appointed First Minister after the May election he said: “This is very much a debate within unionism and I think too much is made of it. We are content to go into an election on the basis of our record and we will see what happens.
“You have to understand the nature of the office of First and deputy First Minister. The two positions are absolutely co-equal.
“The reality is, for this place to work then both people have got to agree. If we are consistently imposing vetoes on one another we are not going to get anything done.”