John Setka quits as CFMEU's Victorian secretary, effective immediately

John Setka will step down as the CFMEU's Victorian secretary, effective immediately, the union says.

The controversial figure at the powerful union made the announcement tonight ahead of a joint investigation by 9News, 60 Minutes and The Age, which is set to be published this weekend and which alleges serious misconduct by some union members.

Setka was sent a list of questions today regarding recordings and text messages that are set to be published at the weekend, 9News Melbourne reporter Mark Santomartino reports.

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The union said Setka's decision was "in response to the ongoing and relentless stories written with multiple allegations whether true or not about this great union".

"I have proudly served this union in the capacity of an official for close to 40 years and as Secretary for the past 12 years," Setka said.

"These stories have been constant, and while I've been the target of many of them, enough is enough, the ongoing false allegations continually do nothing but harm the work this great union does for its members.

"If my stepping down can stop these malicious attacks on our members and officials and allow this great union to continue to fight for our members, for their wages and conditions, so that they go home safely to their families each day, then I'm happy."

The CFMEU has had allegations of misconduct levelled at it in the past regarding Setka.

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In a video interview with Santomartino, Setka insisted that he and his senior officials had done nothing wrong.

"I know it's just all about trying to get me," Setka said.

"I'm hoping by me stepping down a bit earlier, hopefully will stop the barrage and all the false accusations and all the false stories about this great union, and my job is to protect the members and to protect the union."

Setka recently told delegates at a monthly meeting he would not renominate at the next union election late this year, The Age reports, but that exit has now been brought forward.

In the union's official statement, Setka said "no individual is greater than the union".

"I depart knowing I leave this union in the very capable hands of the National Office and Victorian Executive to continue the work for our members.

"To the members of the CFMEU, you have made me incredibly proud, and it has been an honour and privilege to be your secretary, for that I say thank you."