A new "smart" Barbie doll's eavesdropping and data-gathering functions have privacy advocates crying foul.

Toymaker Mattel bills Hello Barbie as the world's first "interactive doll" due to its ability to record children's playtime conversations and even respond once the encrypted audio is transmitted to a cloud server, much in the way that Apple's Siri voice assistant works.

But the microphone-equipped Barbie's new WiFi features are striking some concerned parents as a "creepy" new development.

The Campaign for a Commercial-Free Childhood launched a petition last week to halt the release of the toy, which is scheduled to reach U.S. shelves in the fall and retail for $74.99 US.

About 5,200 signatures have been collected so far for the child privacy advocacy group's online petition.

Girls wanted 'conversation with Barbie'

"Kids using 'Hello Barbie' won't only be talking to a doll, they'll be talking directly to a toy conglomerate whose only interest in them is financial," Susan Linn, the organization’s executive director, said in a statement. "It's creepy—and creates a host of dangers for children and families."

In an online video, a Mattel presenter at the 2015 Toy Fair in New York says the new doll fulfills the top request that Mattel receives from girls: to have a two-way dialogue.

"They want to have a conversation with Barbie," she said, adding that Hello Barbie will be "the very first fashion doll that has continuous learning, so that she can have a unique relationship with each girl."

Hello Barbie, which is still in prototype form, can initiate storytelling and listen, learn and adapt according to a child's playtime preferences.

Asked, "What should I be when I grow up?" during a demo, the doll responded: "Well, you told me you like being on stage. So how about a dancer? Or a politician? Or a dancing politician?"

Its listening function is activated only when a button on Barbie's belt buckle is pressed.

Mattel says Hello Barbie's talkback abilities should only be enabled once parents have given consent by signing into an app, creating an online account and agreeing to allowing data capture.