Construction-company boss George Alex is expected to face a lengthy period in jail over a joint plan with four co-conspirators to defraud the tax office of more than $10 million.
A NSW Supreme Court jury delivered their final verdicts on Tuesday, concluding their role in a mammoth tax fraud trial that has run since February.
George Alex, 53, Pasquale Loccisano, 54, Lindsay John Kirschberg, 65, Gordon McAndrew, 62 and Mark Ronald Bryers, 66, were all found guilty of conspiring to dishonestly cause a loss to the Commonwealth.
The five men have also been found guilty of either conspiring to or intentionally dealing with proceeds of crime worth more than $1 million.
The group used a number of second-tier "shield" companies to hide more than $10 million of pay-as-you-go (PAYG) tax from the Australian Taxation Office between 2018 and 2020.
About $125,000 was deducted per week in the latter half of 2018 and well into 2019 and then kept from the ATO.
Lesser amounts were deducted over Christmas 2019 and into 2020 as the construction business became less profitable.
McAndrew, who was the general manager of the firm's Queensland office, and Kirschberg sent the net pay to workers without remitting the PAYG to the tax office under instructions from their boss.
Loccisano acted as a go-between or messenger, passing information and directions between George Alex and the others.
George Alex's 26-year-old son Arthur was acquitted of conspiring to cause a loss and of conspiring to deal or recklessly dealing with the proceeds of crime.
The jury heard 64 days of evidence and weeks of submissions before deliberating over the verdicts for a further 17 days.
The five offenders will be sentenced at a later date.
