Sir Jeffrey Donaldson said the "bulk" of DUP MPs have not put their names forward to run in the Assembly election.
The DUP leader said it is "not true" to suggest all eight of the party's MPs were considering standing.
It comes amid an angry backlash over the return of dual mandates.
Sir Jeffrey said: "No decisions have been made because we are still going through a selection process at the moment.
"The bulk of DUP MPs have not put their name forward for selection.
"I see some parties saying that all eight DUP MPs will be standing in the Assembly elections - that simply is not true."
Sir Jeffrey added: "Even before I was elected leader of the DUP, last year it was the Labour Party, the sister party of the SDLP, who first put this (Bill) forward.
"Furthermore, it was put forward as a proposal when the NDNA (New Decade, New Approach) Bill was being debated in the House of Lords.
"I have had a look at that debate and I note that none of the parties who are objecting now raised an objection at that time.
"This matter will be debated in Parliament. My first priority is not evading a by-election, it is to ensure Northern Ireland has a strong voice at Westminster and that we get strong leadership at Stormont."
Sir Jeffrey confirmed he would consider the opportunity to serve as both an MP and an MLA if the legislation is passed.
He said: "If this legislation is passed by Parliament, it will be available to any Member of Parliament in Northern Ireland who wants to switch back to the Assembly; it is up to each individual MP.
"If this legislation is approved then I will consider whether I can avail of this option."
The DUP leader added: "I think there is a case to be made at this particular time in the current circumstances of Northern Ireland. It is important for unionism to have a strong voice in the Parliament of the United Kingdom.
"It will be the people who decide this. If I am selected as a DUP candidate and I stand in the Assembly election, and if Parliament approves this proposal, it will be for the people to decide whether or not they think this is a good thing."
South Belfast SDLP MP Claire Hanna said the proposed Government legislation on double-jobbing - serving as both a Westminster MP and a Stormont MLA was a "safety net" for Sir Jeffrey Donaldson.
She told the BBC: "The SDLP's view is very clear, we don't support double-jobbing.
"Jeffrey Donaldson can put up all the straw men that he wants, it is quite clear that the other parties don't support this because it reduces the function of elected representatives.
"These two parliaments run at the same time. You can't do justice to both roles and you are not doing justice to your elected representatives.
"What is concerning people is the fact that this feels very much like a stroke, and it is a stroke to benefit Jeffrey Donaldson.
"The reason Jeffrey Donaldson wants this safety net is because he is dangling the future of the (Stormont) institutions by a thread."