DUP members of Fermanagh and Omagh DUP District Council have lodged a complaint to the Local Government Commissioner for Standards, after an independent councillor brought a proposal against the extradition of Liam Campbell to face weapons smuggling charges.
Campbell was found liable in a civil court for the Omagh bomb in 1998, which claimed the lives of 29 people including a woman pregnant with twins and injured 220 others.
During a meeting of the Fermanagh and Omagh District Council's Policy and Resources Committee last week, Councillor Bernice Swift sought support in opposing Campbell's extradition under human rights.
During the meeting, chairman, Councillor Stephen McCann, permitted the last minute notice of the proposal and refused to allow open debate, moving quickly into confidential business.
The move has left victims of the Omagh bomb "appalled and re-traumatised".
The DUP complaint comes after republican Councillor Gary Donnelly of neighbouring Derry and Strabane District Council indicated his intention to bring forward the same motion.
DUP group leader Councillor Errol Thompson said: "We have lodged our complaint against Councillor Bernice Swift and Councillor and chair of the Policy and Resources committee Stephen McCann.
"We believe the standards of which the public expect of councillors has been profoundly damaged. The proposal raised is not within the remit of the council and should not be accepted as reasonable business for the council to conduct.
"It has instead insulted Omagh bomb victims and upset many within the community."
"There seems to be no end to the lengths some people will go to intentionally hurt and exacerbate grief," said victims campaigner Claire Monteith, who lost her brother Alan in the Omagh bomb.