Leader Naomi Long said the emergence of the Alliance Party as one of the largest in the North raised questions about power-sharing structures.
The DUP coalition was ranked the second most popular party in the region, at 16 percent, in a LucidTalk poll for the Belfast Telegraph this weekend.
Ms. Long said the results «challenge the structures of the association,» which maintains the role of deputy and prime minister for the largest nationalist and unity parties.
It greatly challenges the association structures, which say that if you are not appointed as a unitary or a nationalist, then somehow you are not entitled to represent the people who vote for you, in the same way as other parties.
Major decisions are based on the need to secure a majority for both nationalists and trade unionists, a system that could be undermined if the coalition emerges from the upcoming elections as one of the largest parties.
“Crucially, the coalition continues to erupt in the wake of the DUP, to be the second largest party in Northern Ireland.
«This is an interesting prospect because it massively challenges association structures, which say if you are not appointed unitary or nationalist, then somehow you are not entitled to represent the people who vote for you, in the same way as other parties.
“It could affect, for example, the positions of First Vice and Prime Minister, but it would also affect things like cross-sectarian voting.
“So, I believe that the appointment system in the Assembly has not been subjected to more scrutiny than it is now, given the progress made by the Alliance.
«For me, this is the response that the government should look for in terms of how to accommodate a much larger segment of society that is not classified as federal or national, in a completely democratic and just way.»
Long also questioned the plans of the new leader of the DUP, Edwin Potts, not to take over as prime minister.
And she warns it could make the prime minister appear secondary to the role of agriculture minister, which Mr Potts occupies.
She told the BBC’s Sunday Politics: «I think it’s a bit odd situation where you can have someone in the prime minister’s seat, and you have to make those major decisions, have to speak on behalf of the executive, yet you have to bow to someone.» Another around the executive table.
I think it makes the prime minister seem a bit secondary, possibly, to that of agriculture minister.
Problem with DUP where support drops to give Sinn …
The approval of the Minister of Agriculture will be required for each issue, unlike the Prime Minister who acts on behalf of the party.
“I think this is a difficult split to manage, but the DUP will have to manage it, and it is up to them to make sure it works.
«Because the rest of us certainly do not want to be crippled or affected by any internal problems the Democratic Unionist Party may have.»