The man also behaved and spoke inappropriately during the sessions, the watchdog found.
The incidents all occurred in 2022, and because the therapist claimed on his website to be qualified, he was required to meet the standards of a professional massage therapist, the HDC said.
Three separate customers said they felt uncomfortable and unsafe due to the therapist's behaviour and comments, including talking about their weight.
One complainant, Ms C, saw the masseuse because her regular therapist was off sick.
The session ended with her feeling vulnerable and uncomfortable being "alone in a room with a man who would [not] stop touching/hurting [her] no matter how many times [she] asked him to stop".
The woman said she asked a number of times, "Can I take a break?", "Can I have a minute please", "Could I have a moment?", "I think I need to stop now", and "To be honest, I'm struggling".
"It was very painful so I also asked if he could go lighter a few times, [but] he refused, [saying] that it would tickle otherwise."
The therapist talked a lot during the session, she said, but would ignore her every time she asked him to pause the massage.
In response to the HDC, the therapist said, "Client comfort is paramount, and they are [all] advised that some discomfort maybe involved but that they are completely in charge of this."
The massage therapist also made racist and sexist comments, and engaged in explicit sexual conversations during the sessions.
Another client, Ms B, said the therapist talked for the whole time, and the nature of his conversation was "racist and inappropriate", including the view that Māori "do not exist" as an ethnic group and they were trying to "take over the government".
He also spoke about women and sex, his religious beliefs and the differences between men's and women's "crucifixion practices".
Ms B reported that she wanted to leave, but felt uncomfortable as she was lying down and naked.
A third complainant, Ms A, said her session started with the therapist telling her she needed to lose weight, and that she could have her "body altered surgically to be taller".
Later in the session, there was a "very inappropriate one-sided conversation all about sex", with the therapist speaking explicitly about erections, ejaculations and people having sex, Ms A said.
Deputy Commissioner Dr Vanessa Caldwell found the massage therapist breached the Code of Health and Disability Services Consumers' Rights (the Code) across three separate complaints received by HDC.
"I consider the MANZ Code of Ethics and Standards of Practice to be an appropriate benchmark for the assessment of the therapist's practice," Dr Caldwell said.
The therapist's failure to comply with these standards breached the Code, which gives consumers the right to services that comply with legal, professional, ethical, and other relevant standards.
"There is a clear pattern of inappropriate behaviour by the therapist, and I am very concerned at the prevalence of his unethical behaviour."
Dr Caldwell also found the therapist breached the Code for failing to take the complaints seriously. He failed to provide adequate responses to HDC's request for information and did not engage appropriately with the investigation process.
The case was being referred to the Director of Proceedings to decide whether further action should be taken.