The Office of the Australian Building and Construction Commissioner (ABCC) has secured a record workplace relations penalty of $1.325 million as a result of a legal proceeding initiated by the ABCC in response to a protracted union demarcation dispute at the West Gate Bridge strengthening project in 2009.

The two unions involved, the Construction, Forestry, Mining and Energy Union (CFMEU), the Australian Manufacturing Workers Union (AMWU) and union officials Mick Powell, Tony Mavromatis and Gareth Stephenson consented to pay the penalty for a combined 52 breaches of workplace laws, according to a statement released from ABCC today.

ABC Commissioner John Lloyd said the punishment reflected the serious nature of the unions' and officials' behaviour.

"No Australian employee or employer should have to endure the bullying, abuse, threats of violence and property damage that workers and subcontractors on the West Gate Bridge were subjected to," Mr Lloyd said.

"The ABCC is satisfied with the record $1.325million penalty which has held the unions and their officials accountable for their deplorable behaviour."

"The case will act as a powerful deterrent. If a person or organisation abuse the law and coerce others the matter will be pursued and strong penalties can be imposed."

The respondents had agreed to a settlement with the ABCC and did not refute the evidence of coercive conduct and unlawful industrial action. Such actions constitute offences under the Building and Construction Industry Improvement Act 2005.

In the Federal Court today, Justice Jessup ruled that the evidence showed the respondents had committed the 52 contraventions and the agreed $1.325million penalty was appropriate.