"Also known by the spelling Mishell and also known with the surname Tinsley.
"She has not been in touch with any close friends or family for quite a few days and we are very worried about her."
There was a rumour that she may have been in Queenstown, Feeney said.
"But we are worried for her safety and are desperate to hear from her."
A person who said they were Michelle's daughter posted online that their mother, who lives in Picton, has a permanent head injury and suffers from memory loss.
Blenheim Police urge anyone who has seen Michelle or knows of her whereabouts to contact 105.