A British migrant is accused of posing as a physio during an 18-month period treating unsuspecting patients around Auckland.

Jonathon Steven Mann, who is believed to be in his 30s, appeared before Auckland District Court on Wednesday to face 17 charges laid by the Ministry of Health.

The ministry alleges he performed a "restricted activity" without being qualified or registered between January 2007 and July 2008, including "high-velocity" manipulation of the lower spine.

Mann, whose clients are understood to have included gyms and rugby clubs, is also accused of falsely describing himself as an osteopath and telling clients he was registered as a physiotherapist in New Zealand.

The ministry alleges he was not registered, or qualified to be registered, and launched an investigation after complaints from the public.

The United Kingdom's health professions council said it had "no record of a Mr Mann as a registered physiotherapist".

Mann did not enter a plea and was remanded on bail to reappear in Auckland District Court in June.

The owner of the house given as his bail address said he didn't live there, and was only living there while housesitting last year.

Attempts to find his current address were unsuccessful. During a brief phone conversation on Friday, Mann said he would defend the charges but refused to comment further.

A source who worked with him at an upmarket fitness complex last year said Mann claimed he was completing a doctorate that would make him the "highest qualified physiotherapist in the country".

He said he had several sessions with Mann, who "was very convincing and smooth".

When he asked for Mann's CV or references he was told they were coming from the UK.

Soon after, a health ministry investigator contacted the business owner to alert him to its investigation.

Another patient, who asked not to be named, said Mann had manipulated his back and neck.

When his pregnant wife complained of back pain he suggested she set up an appointment.

Asked if the husband or wife had asked to see references he said: "He seemed smooth, believable and seemed to know what he was doing, otherwise I wouldn't have suggested my wife should go and see him."

Health ministry chief legal advisor Phil Knipe said it routinely carried out investigations following complaints from the public and organisations such as the Medical Council.

In the past three years it had brought several cases before the courts but many investigations didn't result in prosecution.

Three cases were investigated last year and another three are being investigated this year, including the Mann allegations.

The charges that Mann faces carry maximum fines of between $10,000 and $30,000.