"Unionist unity" talks were hosted by the Orange Order last month
Conservative Northern Ireland spokesman Owen Paterson has said he is seeking an urgent meeting with Ulster Unionist leader Sir Reg Empey.
It follows revelations the Orange Order convened secret unity talks between the DUP and UUP in early December.
The parties discussed the possibility of electoral pacts and forming a unionist bloc at Stormont.
However, the talks did not involve the Tories, the Ulster Unionist Party's current election partner.
Mr Paterson said he knew nothing about the meeting which was exposed by the BBC's Hearts and Minds, and would not comment any further until he had talked with Sir Reg.
Earlier this month, Mr Paterson, who is shadow Northern Ireland secretary, chaired secret discussions between the DUP and UUP at Hatfield House in England.
On Tuesday, two former Conservative candidates who withdrew their nominations said it was partly because of a possible deal between the Ulster Unionists and DUP.
There has been speculation that Sheila Davidson and Peter McCann, who are both Catholic, had left in protest at talks hosted by Mr Paterson.
BBC Newsnight political editor Michael Crick
said: "Some in Belfast think that the Conservative-UUP pact is now effectively dead, and that Conservative leader David Cameron will be forced to announce its demise within the next few days."