Party officers are expected to meet on Tuesday to decide the date of the DUP's leadership election.
UTV understands that could be as early as next week.
On Monday, Sir Jeffrey Donaldson announced his leadership bid.
The longstanding Lagan Valley MP will now go head-to-head for the top job with Agriculture Minister Edwin Poots, who also represents the Lagan Valley constituency as an Assembly member.
It will see the first ever leadership contest in the DUP's 50-year history.
Sir Jeffrey said he would promote a positive strategy and values if elected, with a focus on building a shared future for everyone in Northern Ireland.
The party's current Westminster leader also pledged meaningful reform within the DUP and said he would set clear policy directions on key challenges for unionism, such as Brexit's contentious Northern Ireland Protocol.
We want to build a shared future for Northern Ireland where everyone, regardless of their background, has a part to play in showing the world what we are truly capable of.
Environment Minister Edwin Poots said he wanted to "rebuild, revitalise, reinvigorate and revive" Northern Ireland.
"I am a proud Northern Ireland man, I love its people and its place, and it faces many challenging times, it’s with that in mind, I’m putting my name forward for the leadership for the Democratic Unionist Party,” he said.
Northern Ireland is a place that has had many great things over this last hundred years, I wish to see us rebuild, revitalise, reinvigorate and revive for the next hundred.
Sir Jeffrey will be seen as the moderate candidate against the more hardline Mr Poots.
The party's outgoing leader Arlene Foster resigned last week after an internal revolt against her leadership.
The move came in the form of a letter of no confidence signed by a majority of the party's senior elected representatives.