Online comments labelled the woman in the videos "disgusting" and a "horrible human being" and police are now investigating.
Detective Inspector Scott Beard, Auckland City Police, told the Herald that police are making enquiries.
"We ask anyone with information relating to the identity of the person who posted these videos to please contact Auckland Police on 105.
"The comments made in the video are offensive and would be extremely upsetting to Grace's friends and family and to the wider community."
READ MORE:
• Grace Millane verdict: Guilty of murder, justice for her family
• Grace Millane murder trial: Jury returns guilty verdict and brings justice to backpacker's family
• Woman who went on Tinder date with Grace Millane's killer speaks out
• Millane murder verdict: Murderer's stepbrother 'shed tears' at result, but pleased justice served for Grace
Millane's killer was found guilty of her murder last month, after a three-week trial.
The British backpacker was strangled to death on the eve of her 22nd birthday by her Tinder date in his downtown Auckland apartment on December 1 last year.
He then went about trying to cover it up and dumped her body in the Waitākere Ranges.
He will be sentenced on February 21 next year.
Millane's parents, seated in the first row of the public gallery, broke down in tears and embraced each other as they heard the word "guilty" from the jury foreperson.
David and Gillian Millane spoke to dozens of journalists from around the world after the verdict.
David said their lives had been ripped apart.
"This will be with us for the rest of our lives," he said. "Grace was a beautiful, talented, loving daughter. Grace was our sunshine and she will be missed forever."
His only daughter, he continued, "did not deserve to be murdered in such a barbaric way in her OE year".
