The former Ulster Unionist deputy leader is expected to replace Mike Nesbitt, who quit on Tuesday amid a row with party leader Jon Burrows.
Ulster Unionist MLA Robbie Butler is set to be named as Stormont health minister.
The anticipated appointment of the Lagan Valley representative comes after Mike Nesbitt resigned from the post amid a fallout with UUP leader Jon Burrows over the proposed withdrawal of emergency general surgery from Causeway Hospital in Coleraine, Co Londonderry.
Mr Burrows said he did not support the removal of the services during a townhall meeting last week, making clear his opposition to the plan recommended by health trust bosses.
Mr Nesbitt, who had not yet confirmed whether he was going to push ahead with the withdrawal proposal, responded with a hard-hitting resignation letter.
The Strangford MLA accused Mr Burrows of imposing a “red line” over the proposed hospital reconfiguration plan, adding he was not going to be a minister who learned about his party leader’s views on key issues through the media.
Mr Butler is a former deputy leader of the UUP who worked as a firefighter prior to entering politics.
Speaking to the media at Stormont on Wednesday, Mr Burrows said he was “disappointed” Mr Nesbitt decided to resign and insisted he had still been “prepared to work” with him as minister.
A number of health bodies have expressed alarm at the resignation, describing it as coming at a “particularly challenging time” for the health service.
Roisin Coulter, chairwoman of the NI Confederation for Health and Social Care, urged the next minister to continue to back the Department of Health’s reset plan, which she said is “overwhelmingly supported by our members”.
An emergency meeting of the Assembly’s Health Committee has also been convened for Thursday afternoon when senior officials within the Department of Health will face questions from MLAs.
