Vince Santoro, the man behind Elite Civil Group, has not been seen or returned calls since mid-February. Angry sub-contractors claim he owes at least $5 million in unpaid debts to more than 50 firms.
Creditors said he had received millions of dollars in progress payments since Christmas but that none of that had gone to pay his workers or sub-contractors.
Proceedings have begun in the Federal Court of Australia to wind up Elite Civil Group and its associated companies.
At least one creditor has taken matters into their own hands. In further evidence of underworld involvement in the construction industry, Fairfax Media has learnt that standover men and members of outlaw bikie gangs turned up to seven construction sites across Sydney linked to Mr Santoro over the past month.
After an initial stand-off with security guards at one site at the end of February, bikies and associates loaded all the machinery onto trucks and drove off - taking items even belonging to plumbers and trucking companies who were also owed money.
Aside from creditors, Elite Civil Group and its associated companies is understood to owe hundreds of thousands in unpaid wages and entitlements to its workers.
The firm is allegedly linked to well-known Sydney mediator Alex ''Little Al'' Taouil, who refused to comment when contacted about Mr Santoro. Mr Taouil's solicitor said that his client was ''a victim in all of this just like the other employees''.
Fairfax Media was unable to reach Mr Santoro for comment.