Last Updated:A Northern Marianas human rights advocate says Asian women make up most of the sex trafficking victims in the commonwealth.
In the latest Trafficking in Persons report by the US State Department, Tonga has been added to the list of Pacific countries where human trafficking is considered a problem.
The Northern Marianas (CNMI), Guam and American Samoa have also been listed, while the Federated States of Micronesia's status has been downgraded.
The report says that in many cases, women are recruited to other countries with promises of well-paying jobs and then are forced into prostitution.
CNMI human rights activist Wendy Doromal told Radio Australia's Pacific Beat the trafficking of women is a widespread problem.
"Most trafficking victims are from the Philippines, China and other Asian countries," she said.
"They are usually victims of illegal recruitment and they are brought to work in clubs, restaurants or massage parlours."
Ms Doromal says sex trafficking victims have "no voice, no vote and no social or political rights."
"The employers know this - the illegal recruiters know this - and (the women) are taken advantage of and will (continue to be) taken advantage of until they are afforded some social and political rights."