The construction sector union says it will take immediate action if it's made aware of any illegal or corrupt activity by its officials.
A joint ABC-Fairfax Media investigation has found union officials are making corrupt deals to help companies linked to organised crime secure construction contracts.
Victoria's desalination plant and the Barangaroo development in Sydney are among a number of projects that companies connected to major crime figures are reportedly involved in.
The report implicate a number of Construction, Forestry, Mining and Energy Union (CFMEU) members in NSW and Victoria in dodgy deals, including bribery and extortion.
CFMEU National Secretary Dave Noonan says the union acts in the interests of workers at all times.
"The vast majority of our officials are hardworking people who are dedicated to improving the lives of construction workers," he said in a statement on Tuesday.
"If the leadership of the CFMEU is made aware of improper, illegal, corrupt or criminal activity by any official of the union, we act immediately."
The union has terminated the employment of officials who have engaged in such activity in the past, he said.
"We would not hesitate to do so in the future, if warranted."
The CFMEU has adopted new governance rules for our officials which have been ratified recently, he said.
Mr Noonan says he wants to see a full police investigation of any allegations.