Concerns are being raised of "underground" beauty clinics operating in Auckland, where unqualified people are performing cosmetic surgeries and using unregistered medication.
Sources who wished to stay anonymous told the Herald they had lodged complaints to various authorities, including the government regulatory body Medsafe.
Derek Fitzgerald, Medsafe compliance manager, confirmed that in the past 24 months, two seizures of stock had been made and one official warning letter was issued.
"Medsafe has received information about activities in this area and Medsafe staff have been in contact with the complainant," Fitzgerald said.
"We have previously had discussions with the NZ Society of Cosmetic Medicine as part of our ongoing monitoring of issues in regards to medicines and medical devices used in cosmetic medicine."
Fitzgerald said until the investigation was complete, the body was constrained on what it could say.
One Auckland woman, who is advertising surgeries on Chinese social media site WeChat, was promoting cosmetic medicines and products which were not registered for use here.
Several sources in the industry said the woman claimed to be a doctor, but did not have any qualification or medical training.
The woman had been operating in the CBD, but is believed to have moved the operation to a private suburban address.
She could not be contacted, and did not respond to messages sent to her on WeChat, where she is promoting her business.
Based on screenshots seen by the Herald, the woman is believed to be using an unregistered product similar to botox and importing dermal fillers.
Her advertised services include nose reshaping, fat transfer and facial threading.
Also on WeChat, another woman was also promoting other unregistered cosmetic products and procedures she may not be qualified to perform.
Sydney woman Jean Huang died after a botched breast procedure by a Chinese visitor claiming to be a doctor in August.
Anaesthetic and breast fillers were administered on Huang by the tourist, who was not qualified to do them.
Fitzgerald said people could complain to the Ministry of Health if they were concerned about medicines or medical devices used in relation to a cosmetic surgery.