The warning came after violent scenes between Construction, Forestry, Mining and Energy Union (CFMEU) protestors and police stemming from a dispute over an enterprise agreement and safety stewards.

AMMA executive director Minna Knight said the federal government needed to act to ensure these events weren’t repeated.

“Images of today's illegal union protests and militant activity will be projected on to television screens around the world,” Knight said.

“What message does that send to multinational companies about investing in Australia?”

Knight referred to the federal government’s decision to abolish the construction industry watchdog, known as the Australian Building and Construction Commission (ABCC), earlier this year, saying the resources industry had warned there would be severe economic repercussions.

“There are $A260 billion worth of advanced resource projects in Australia's pipeline, with a vast level of that investment in construction works over the next three to five years,” Knight said.

“Without the ABCC and the ability to often prosecute militant individuals behind such illegal action, the 90,000 new construction jobs forecast on these resource projects remain under threat.”

AMMA’s comments come a day after Grocon boss Daniel Grollo told the AFR that the CFMEU’s Melbourne blockade was over the construction company’s refusal to pay for union-appointed stewards on worksites.

Knight said it appeared Australia had gone back to the dark days of one set of rules for union bosses and one set of rules for everyone else, fuelling more challenges for Australia’s investment environment.

“Productivity will decline even further and costs will escalate,” Knight said.

“Restoring an effective construction industry watchdog is a necessary step if Australia is to secure its strong pipeline of resource projects.”