LABOUR Party members say they are being evicted from the party for backing independent AM Peter Law.
He won Blaenau Gwent constituency at the general election ahead of the Labour candidate who he opposed in a row over all-women shortlists.
Welsh Labour said 20 members in Blaenau Gwent now faced expulsion.
Welsh Secretary Peter Hain said there would be no "vendetta" against former party comrades who supported Mr Law.
But his predecessor, former Blaenau Gwent MP, Llew Smith, told BBC Wales yesterday, "It's a disgrace. The people who inflicted this policy on Blaenau Gwent should be punished, not the people who had the courage to stand up and make their voices heard. It is a crazy witch hunt by the party in Cardiff."
Steve Osborne, Blaenau Gwent Labour secretary, said he understood letters of expulsion will be sent from party headquarters in Cardiff.
It is understood grounds for expulsion from the party include actions such as signing Mr Law's nomination papers.
After overturning Labour's safest seat in Wales with more than a 9,000-strong majority, Mr Law signalled he might reconsider rejoining the party if the opportunity arose. However he has accused the party of intimidating his campaign team for supporting him as an independent socialist.