The national tier of the construction union is backing rogue union boss John Setka, following a meeting of executives.
Labor leader Anthony Albanese moved to expel Mr Setka from the party over accusations he told colleagues anti-family violence campaigner Rosie Batty's advocacy has led to men having fewer rights, allegations rejected by Mr Setka.
But the CMFEU is sticking by their man, releasing a statement late on Wednesday night saying Mr Setka "has the full support of the Construction and General Division"
"The Construction and General Division strongly condemns the use of untruthful leaks from the NEX (national executive)," it said in a statement.
"At no time at the NEX meeting on June 5 did John Setka criticise or denigrate Rosie Batty or indeed any campaign against family violence. John's heartfelt account of his personal life in recent months was received by most in the room in the same genuine spirit in which it was delivered."
The statement comes after the Victorian branch of the CFMMEU asked the national arm to publicly support Mr Setka and to forensically investigate the "cowardly manufactured leaks" from the meeting where the comments about Ms Batty were allegedly made.
Earlier on Wednesday Mr Albanese secured cross-faction support for his bid to oust the embattled union boss.
Labor's shadow treasurer Jim Chalmers, from the right faction of the party and aligned with the Australian Workers' Union, on Wednesday broke silence on the issue to support Mr Albanese, a left-winger, "100 per cent".
"I think that's a very good decision - I think the community will support that decision," he told reporters in Mackay.
However, Mr Chalmers says Mr Setka's role at CFMMEU is a matter for union members.
Victoria's CFMMEU has vowed to end all financial support to the ALP if Mr Setka is expelled from the party and to cut ties with unions that have "attacked the branch".
The union boss has threatened legal action and a long battle if Mr Albanese moves against him.
But the Labor leader is standing his ground and says he doesn't respond to threats.
"The fact that threats are made perhaps reinforces the fact there's a problem, if people think that's the way to engage," Mr Albanese told 2GB radio.
"I think it says more about the people making the threats than those receiving them."
Victoria's manufacturing, electrical trades, rail and transport, plumbers and firefighters unions declared their support for Mr Setka on Tuesday, saying he should stay in his role unless his members decide otherwise.
The unions are calling for the issue and decisions on Mr Setka's position to be left to members.
Mr Setka faces court on June 26 when he is expected to plead guilty to two criminal charges, including one of using a carriage service to harass a woman.
ACTU secretary Sally McManus is demanding Mr Setka resign with the leaders of the three largest unions - representing mainly female workforces - following suit.
The AWU backs them but wants proper processes followed.
Australian Associated Press