According to newspaper Correio da Manhã, Australian police believe the pair made around €1.7 million in profit, part of which they gave to the Hells Angels bikers’ gang, of which the brothers are said to have been members.
Local press reported Bruno and Nuno da Silva, 38, were handed jail terms of nine and seven years respectively.
They were detained in October 2013 following a police crackdown on motorbike gangs.
Bruno was reportedly considered the mastermind behind the 16-month-old trafficking set-up; Nuno could be released on parole next month.
The brothers are understood to have used their connections to Hells Angels to force clients to pay debts and gave part of the profits to the group, communicating in code.
Police first became suspicious of their dealings in 2004 when Bruno was caught with €87,000 in a bag, which he said were gifts from his brother’s wedding to a lawyer.
In 2012 they were allegedly beaten up by a rival gang.
However, in court, prosecutors said they had no idea where the €1.7 million had gone to.