It comes one week after Warriena "Rrie'' Wright, 26, was killed in the fall from the Avalon apartments in Surfers Paradise about 2.20am on Friday last week.
Police took Tostee into custody for questioning this afternoon, but a Gold Coast police spokeswoman said no charges had been laid.
"A 28-year-old man is currently assisting police with inquiries in relation to the incident,'' she told APNZ.
Tostee arrived at the Southport Courthouse on the Gold Coast in the back of an unmarked police car.
Handcuffed, wearing shorts and a white T-shirt, he was led through a side entrance into the court building, shortly before 12.30pm local time.
Ms Wright, who was on the Gold Coast for a close friend's wedding, had been at the bodybuilder's apartment after meeting him on the dating app Tinder.
Tostee left the apartment the morning of the death but later contacted police. He was released without charge.
Police have scoured his apartment for forensic evidence and seized hard drives, discs and a camera.
They have also been monitoring Tostee's posts on social media, where he denied causing Ms Wright's death and bragged about his past sexual conquests.