The Women and Children Crisis Centre in Tonga says the kingdom needs to open its eyes up to the trade in sex workers and it's doing its own investigation to build up evidence of the problem.
The Centre's Director, Ofa Kilevuka Guttenbeil-Likiliki, says it's aware Chinese women lured to work in the tourism industry are forced into prostitution and the trade's been highlighted in a recent court case.
But the centre has no idea of the numbers involved so it's started researching the problem.
"It's a very sensitive issue so it's going to be handled very carefully. The most important thing is we have to build the trust of these women to confide in us. Confidentiality will be a very major part of this whole research."
Ofa Kilevuka Guttenbeil-Likiliki says Chinese interpreters have been engaged and centre literature translated so the migrants know where to go for legal and medical advice.
She says the centre also wants to raise awareness among Tongans generally about the sex trade as local women are also vulnerable.