The Ulster Unionist Party (UUP) leader has said he is disappointed no non-party, cross-community candidate will contest the West Tyrone by-election.
Robin Swann said others had not engaged on the issue ahead of the Westminster poll next month.
The election follows the resignation of Sinn Féin MP Barry McElduff.
He stepped down after he was widely criticised for posing with a Kingsmill loaf on his head on the anniversary of the Kingsmill massacre by the IRA.
Mr McElduff apologised for his actions, saying that he did not make a connection in his mind between the video and the IRA murders.
The nominations to replace him are due to close on 10 April.