The 20-year-old actress, who is dating heartthrob Zac Efron, said: "I will show nudity in a film when the time is right. Right now, I wouldn't feel comfortable doing it.
"When the time's right, if it's an amazing movie that I'm really passionate about and that's what it calls for, then we'll see."
Although she doesn't feel it is appropriate for her to strip off now, explicit photos of Vanessa have already been seen.
In September 2007, pictures of her posing provocatively in lingerie were leaked on the internet, as well as one naked shot.
She later apologised for the images, saying she was "embarrassed over the situation" and regretted having "taken those photos".