In the latest twist in a bitter dispute at Ballynahinch Congregational Church, the trustees challenged Rev George Speers to enter mediation talks.
In a statement, chairman of the trustees Richard Payne and secretary Jim Magowan accused Rev Speers of having "fallen well short" of the principles and practices of Congregationalism.
The trustees spoke out in response to Rev Speers' strongly-worded statement last week in which he said he had no intention of standing down as minister.
Years of tension erupted during a sermon at the start of the month when Rev Speers was jeered with chants, whistles and shouts of "out, out, out" during an angry exchange between rival factions.
The minister continued with his sermon, at one point using a megaphone to be heard over the noise. Police had to storm into the church to break up the protest.
Last night, the trustees admitted the protests on September 1 were a mistake.
"The protests were wrong but they do give a clear indication that the refusal of George Speers to allow discussion and a process of mediation has led a congregation to breaking point," they said.
Last Sunday, around 60 of his opponents walked out of his morning sermon. It followed Rev Speers' defiant statement in which he declared that accusations made against him were false.
He also said he had attempted to resolve the row through the use of internal church structures, and had engaged in talks facilitated by third parties.
"Sadly, a resolution accorded with biblical principles could not be found," he added.
But the trustees said at least four offers to discuss the disputed issues had been rejected by Rev Speers. They described negotiations in August as 'proximity' talks that had no legal force.
"The trustees have already accepted the recent offer of mediation through the Congregational Union of Ireland and await a response from George Speers."
Rev Speers was unavailable for comment.