The majority of the Blaenau Gwent Labour Party Executive have announced they will stand down in protest over the selection of a new Westminster candidate from a women-only shortlist.
More than 40 protesters picketed the shortlist meeting last month
Eight of the twelve members decided that they would resign in March next year after 80 Labour members in the south Wales constituency voted to select London union official Maggie Jones on Thursday.
Local party members insist she is not a legitimate candidate, but the move was taken in an effort to boost the numbers of female Labour MPs.
Following a meeting on Friday night, the Senior Vice Chair, Don Wilcox, said the members who had decided to stand down were "not trying to destroy the constituency" but wanted to make their feelings heard in a "reasonable manner".
Llew Smith MP - who will retire at the next general election - said Ms Jones should not have been selected.
"How can anyone claim to the Labour candidate for the Blaenau Gwent Labour Party when only 10% of the membership voted for her, and when 85% boycotted the election process and refused to vote?", he asked.
But Ms Jones has said she is confident the party will get behind her, and hopes she can persuade local Assembly Member, Peter Law, not to stand against her as an independent candidate in the next election.
Eight will stand down
He still has not ruled out that possibility. He has criticised the selection process and joined protesters outside Ebbw Vale leisure centre on Thursday night.
Welsh secretary Peter Hain described Ms Jones as "one of the Labour and trade union movement's most promising women trade unionists".
And, he added : "She will give a powerful national voice to the people of Blaenau Gwent on issues like low pay and poverty where her union has such a distinguished record of achievement.
"Maggie stands in the long socialist tradition of Nye Bevan and Michael Foot."
First Minister Rhodri Morgan added :
"Maggie Jones is an outstandingly gifted candidate, with her roots firmly in the valleys.
Ms Jones is hoping to gain the local party's support
"Her record as a trade unionist stands her in good stead, and I'm sure she'll be an outstanding MP for Blaenau Gwent and for Wales."
Ms Jones is originally from south Wales, but works in London for the public sector union Unison.
She told BBC Wales she hoped gain the support of all local Labour members.
"I think I would have been a good candidate whether or not there was an all-women shortlist," she said.
"The fact that I was selected on this basis doesn't make any difference.
"I will be a good candidate for Blaenau Gwent and I have got to prove myself now and I hope to do that."
The Blaenau Gwent constituency is one of three in Wales with retiring MPs where Welsh Labour has decided to have all-women shortlists.