Peter Robinson dismissed the latest controversy over who will become first minister as an electoral tactic today.
Sinn Féin's Martin McGuinness has said creating joint first minister posts is an option which could be looked at after the election.
Sinn Féin may become the largest in the Assembly after the May poll.
Mr Robinson said: "It is fairly clear that they are concerned that the unionist population is rallying around the DUP and they are trying to undermine it.
"It is an electoral tactic, people do these kind of things."
Ulster Unionist leader Tom Elliott has disclosed proposals for a post-electoral pact with the DUP if Sinn Féin was to become the largest party. Mr Robinson rejected it.
"The suggestion put forward by Tom Elliott is a non-starter because he committed himself to his party that he would not have any merger with the DUP while he was leader," he said.
"We are in the election to win. I want the DUP to be coming out on top, we are going out to succeed and we are looking for the future of the people."
He said under the St Andrews Agreement it was the party with the largest designation (unionists) which named the First Minister.
The DUP leader said he had not raised the issue of positions in the next executive but added people could lend the DUP their votes to ensure Sinn Féin did not name the next first minister.
"I want the DUP to be the largest party in Northern Ireland, not just because it means we hold the first minister post, it means we have the first choice of departments, it means we go around the world speaking on behalf of Northern Ireland, every party will seek to ensure it becomes the largest party," he added.