And in a separate case, a Sydney man has also been charged with human trafficking, accused of stranding his wife and child in Pakistan.
The PNG-based woman, who is a dual Australian-Nigerian citizen, was arrested when she arrived at Brisbane Airport from PNG on Wednesday.
The 15 PNG nationals who moved to Australia to study were instead forced to work against their will between 2021 and 2023, with some working seven days a week and up to 10 hours a day, federal police allege.
The 56-year-old woman is accused of luring them to Queensland on the promise of education scholarships.
The students, aged from 19 to their mid-30s, were allegedly forced to sign legal documents and agree to repay costs associated with tuition, airfares, visa applications, insurance and legal fees. She also allegedly threatened family members in PNG.
The woman allegedly forced the students to work on farms across Queensland - contravening their visas - and received wages on their behalf as repayments for their debts.
Australian Federal Police called the allegations disturbing.
"These are individuals who are young, that's a point of vulnerability," AFP Detective Superintendent Adrian Telfer said.
"They're extremely isolated. They are pursuing an education, a dream to come here to Australia, opportunities that they don't get in their own country, and they're placed into a position that they weren't prepared for and didn't know how to get out of."
Some of the victims were still in Australia and were being supported by the Red Cross, he said.
The woman appeared in Brisbane Magistrates Court on Wednesday charged with 31 offences and was granted bail to reappear on September 19.
The charges include four counts of trafficking in persons, which each carry a maximum penalty of 12 years' imprisonment, and 13 counts of debt bondage, which is a form of modern slavery.
In the Sydney case, the AFP alleged a 45-year-old southwest Sydney man deliberately stranded his wife and one-year-old child in Pakistan.
After they travelled together to Pakistan in August 2024, the man cancelled his wife's Australian visa and retained his child's passport, then returned without them, police allege.Â
The wife returned to Australia in February and reported the matter to authorities, who helped the child also return.
The man was arrested at a home in Austral, in southwest Sydney, on Wednesday and charged with human trafficking offences.
He faces two counts of trafficking a person by using deception, and a single count of dealing with identification information involving the use of a carriage service.
The man was set to face Liverpool Local Court on Thursday.
Federal police urged anyone who had been through something similar to contact authorities.
