The Liberal leader told the Victorian Liberal State Council he planned to send a clear message that illegal behaviour on building sites would no longer be ignored.

"To let the militant unions of this city and state know that the rule of law must always prevail, we will re-establish the ABCC and finish the job,” he said.

“The law must be supreme, no one is above the law."

Abbott’s comments came just days after the Victorian Supreme Court convicted the Construction, Forestry, Mining and Energy Union of contempt of court for illegally blocking access to Grocon sites during its bitter dispute with the building giant last year.

Victorian Supreme Court judge Anthony Cavanough ruled that 30 charges against the CFMEU had been proven in relation to its blockade of the Melbourne Emporium site and a Footscray development site in August and September 2012.

The industrial protests saw Melbourne's CBD brought to a standstill for two weeks as hundreds of construction workers and union officials took to the streets.

When making his ruling, Cavanough said there had been no ambiguity when a CFMEU official called to the crowd over a loudspeaker: "Back here tomorrow boys for more fun."

"He was plainly inciting the crowd to return to the Emporium site on the next day and to conduct themselves in much the same way," Cavanough said in his judgement.

Grocon chief executive Daniel Grollo mirrored Abbott’s opinion that illegal union behaviour must be addressed, saying the decision was "vindication" for Grocon employees who had not taken part in the protests.

"The CFMEU should now understand they are not above the law and that the intimidation of an entire workforce to achieve their political objectives has no place in modern society," Grollo said.

The Victorian government, which joined Grocon in the legal action, welcomed the ruling.

"Today's decision demonstrates that no organisation in Victoria can consider itself above the law, regardless of its political or industrial influence," a government spokesman said.

"Lawlessness on Melbourne's streets and defiance of Supreme Court orders can never be acceptable and should be opposed and condemned by all sides of Parliament that believe in the rule of law."

Federal opposition workplace relations spokesman Eric Abetz also welcomed the ruling, further reiterating Abbott’s calls to re-establish the ABCC.

"Grocon and the Victorian government are to be commended for standing up for the rule of law," he said.

Grocon had sought $10.5 million in losses suffered as a result of the dispute.

A hearing on appropriate penalties for the union has been adjourned to a later date.