The four church leaders, from the town's Presbyterian, Methodist, Church of Ireland and Catholic churches, had come under fire for initially agreeing to attend a civic service on Friday whilst turning down an invitation to join a service on Sunday organised by the victims' families.
Their decision was heavily criticised by the Omagh Support and Self-Help Group, which is run by the victims' relatives. The church leaders confirmed they will now attend both services after meeting on Monday night to re-think their position.
A number of families have decided to stay away from the Friday service after a fall out with the council over the wording on the new memorial.
Monsignor Joseph Donnelly, a Catholic leader in Omagh, explained the church leaders' change of heart.
"We had originally put our weight behind the council ceremony in the hope that would be a unified event," he was quoted as saying by the Belfast News Letter.
"But it has become clear in the last few weeks some families would have found attending that event extremely difficult.
"So our decision [to attend the Sunday service] is a pastoral response to the situation."
Friday marks 10 years to the day since the Real IRA car bomb attack in Omagh's shopping district killed 29 people, including a woman pregnant with twins.
The service on Friday will be joined by former Lebanon hostage Terry Waite, who will give an address, and followed by the opening of a new memorial at the bomb site and a garden of remembrance close by.
