The DUP MLA Jim Wells has said his party “shouldn’t go into power” if Sinn Fein becomes the largest party and takes the First Minister seat.
Mr Wells told the Nolan Show it was his “personal opinion” but claimed it is also “held by several others at senior level in the party”.
He revealed the party are at “the initial stage of policy development” on the issue and said a “difficult decision” has to be made by the DUP on the issue.
All the main unionist parties have previously refused to confirm whether they would go into an Executive if Sinn Fein becomes the largest party.
Northern Ireland’s next Assembly election is scheduled for May next year and recent opinion polls have indicated that Sinn Fein could emerge as the largest party.
This would mean it would be entitled to nominate for the First Minister post for the first time, with the deputy First Minister role going to the largest unionist party.
Both the First and deputy First Minister posts have equal powers and one cannot be in office without the other.
Mr Wells claimed Sinn Fein holding both the First Minister post and potentially the position of Taoiseach in the Republic of Ireland would be a source of “huge political kudos”.
“We [DUP] haven't made our mind up on our issue we will eventually and make it known,” Mr Wells said.
“I personally would have enormous difficulty with a Sinn Fein First Minister, particular if Sinn Fein also became prime minister in the Republic. That would cause huge difficulties for unionism.
“Whether we like it or not that will very much be in people's minds when they come to vote in May.
“We are only at the initial stage of policy development these are all the arguments that will have to be taken into account before a final and indeed a very difficult decision has to be made.
“If I have a vote in the process, I will be saying I believe we shouldn’t go in and help that Sinn Fein propaganda.
“Obviously we need to make that clear before the election takes place. The manifestos haven't been published we are just starting the election campaign.
“If it is not important and the posts are equal why are Sinn Fein bursting a blood vessel to become First Minister?
“They know the huge political kudos that would occur if they were prime minister in the Irish Republic and First Minister in Northern Ireland.”
In response to Mr Wells, Alliance Party Assembly candidate Sorcha Eastwood said she “can’t believe” what she heard from the South Down MLA.
“I know people right across Northern Ireland will be listening to the show this morning and going: ‘That is not what we want for this place, that is not what we want for our future’,” she said.
“Put people first that is what this is all about we will go into government with whoever. Anything less than that is unacceptable.”
TUV leader Jim Allister said all the main unionist parties in Northern Ireland should not “take any office until there is reversion to the First Minister coming from the biggest community”.
“Polls clearly show that there will be more unionists than nationalists in the next Assembly and therefore it would be undemocratic to allow a Sinn Fein First Minister,” Mr Allister added.
“I repeat my proposal for a pre-election pan unionist pledge that if faced with such a possibility no unionist will take any office until there is reversion to the First Minister coming from the biggest community. This was the original situation under the Belfast Agreement.
“The symbolism of a Sinn Fein First Minister is seen as important to many, even for those who support the absurd Stormont system.”
Responding, a Sinn Fein spokesperson said: “It will be for the people, and only the people, to decide who becomes First Minister in line with the terms of the Good Friday Agreement.
“What the public need to know is will the DUP respect the ballot box and the democratic will of the people?”
The DUP has been approached for a response.