The woman dismissed her niece's claim, saying she made the story up, they said.
The aunt, Phiangjai Phanpplado, 37, surrendered after arriving at Suvarnabhumi airport from South Korea and denied any wrongdoing, Anti-Human Trafficking Division (AHTD) chief Pol Maj Gen Chawalit Sawaengphuet said yesterday.
"The accusation is totally groundless. The truth is [the niece] was willing to go to work at the Seoul massage parlour and her mother was also well aware of her daughter's decision," Ms Phiangjai said.
She also denied allegations that the massage parlour where the 17-year-old worked was actually a brothel and that the girl was forced to sleep with customers.
The girl's mother had also worked at the same massage parlour in the past, Ms Phiangjai said.
"Her mother was the one who allowed her to travel to Seoul with me. We hadn't had any quarrels or problems throughout the girl's stay in Korea, so I was surprised to learn she had lodged a complaint with police," the aunt said.
The girl probably wanted to return home but did not tell her and instead told a police officer in Thailand via Facebook, Ms Phiangjai said.
She said she was not considering filing a lawsuit against anyone - neither the police officer who took the girl's Facebook complaint seriously and sought help rescuing the girl, nor the girl's parents.
Pol Maj Gen Chawalit said since the girl and her aunt told totally different stories, officers would have to question the girl again.
The girl returned to Thailand on May 18 with the help of Thai authorities in Seoul after the AHTD sought their help.
Police have pressed five charges against Ms Phiangjai, namely human trafficking, procuring prostitutes, procuring prostitutes involving a minor aged under 18, detaining someone for forced prostitution purposes, and forcing someone into something and reaping profits from it.
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