The entire DUP officer team in South Down have quit the party to back TUV's Stormont election candidate in the constituency.
Seven officers resigned to oppose DUP candidate Diane Forsythe and instead support TUV’s Harold McKee.
It comes after retiring South Down MLA Jim Wells quit the DUP after endorsing Mr McKee in the election battle.
Read more: Arlene Foster launches scathing attack on Jim Wells as he backs TUV election candidate
The DUP officers who have resigned accused the party leadership of failing to properly consult with them.
Chairman Roland Wilson told the Belfast Telegraph that local DUP members had been "treated with disdain" and were not consulted about the nomination of Ms Forsythe.
Former DUP First Minister Paul Givan said he was sorry to see the local party officials leave but warned unionists of the "risks of splitting their vote" in South Down.
Mr Givan, who is seeking re-election in the neighbouring Lagan Valley constituency, told BBC Radio Ulster: "I'm sorry to lose the individuals that have walked away from us in South Down.
"I am confident though in South Down the unionist community, where they know there's only one unionist seat, they know the risks of splitting their vote in that constituency, and I believe that Diane Forsythe will get elected.
"Because every vote for the DUP is going to matter, not just in South Down, but it's going to matter right across Northern Ireland so that we can pursue our progressive agenda whenever it comes to delivering at Stormont.
TUV leader Jim Allister told the Belfast Telegraph there was a "continuing groundswell of support" for Mr McKee.
He said the TUV candidate was building the "foundation for a great victory for unionists of conviction in South Down".
Mr McKee, who in 2016 briefly served as the UUP's South Down MLA, quit the party last year after saying his Christian beliefs were at odds with Doug Beattie's leadership.
The Newry, Mourne and Down councillor hit out at Mr Beattie's stance on abortion, same-sex marriage and a vote at Stormont on gay conversion therapy.
He subsequently defected to TUV.
Read more: Arlene Foster launches scathing attack on Jim Wells as he backs TUV election candidate
Read more: Jim Wells backs TUV Assembly election candidate
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