During the eight-week trial the prosecution said five Thai women, who cannot be named, were brought into Australia with the promise they would eventually be able to work legally in the sex trade.
But the women were told they first had to work off a debt of about $45,000 each, which meant performing sex acts for no pay.
He said he also took into account that Tang had no prior convictions and the five victims were well provisioned for and fed.
Tang was one of the first people charged under federal anti-slavery laws introduced in 1999.
Common types of labor trafficking include people forced to work in homes as domestic servants, farm workers coerced through violence as they harvest crops, or factory workers held in inhumane conditions with little to no pay.