Christian prayer and traditional Maori healing are to be offered at Whanganui Hospital as part of a natural therapy service - but a sceptic says they could do more harm than good.

Hospital staff will trial the service focused on spirituality and the healing and strengthening of the mind for three months before the district health board considers opening it up to patients.

Reiki, massage and meditation will also be available, Maori health director Gilbert Taurua said.

"This isn't about trying to replicate or duplicate anything that our medical practitioners are providing, it's trying to deal with the person in the whole, a holistic approach.

"Secondly, we're trying to, not normalise, but encourage people to think about those natural ways that people have done for years."

However, Victoria University biology sciences professor Shaun Holt said the therapies were a "strange mix". "Meditation and massage great - the others not so."

There was no evidence-based research on reiki, Christian prayer and Maori healing being useful.

"What annoys me with things like this is there are lots of useful complementary therapies out there that they could be offering - yoga, tai chi, herbal supplements, even acupuncture or traditional Chinese medicine, that are all evidence-based."

He described reiki - which involves the practitioner placing their hands lightly on the body, supposedly allowing a free flow of universal energy - as "witchcraft".

That was a term also used by Whanganui District Health Board member Michael Laws, who described the therapy service as a "seriously stupid decision that hasn't gone anywhere near the DHB board table".

Fellow board member Clive Solomon suggested the hospital "should pay some attention to getting proper standards of care and empathy in conventional Western medicine (which is sorely lacking) first before embarking on bone-throwing with taxpayer money".

Prof Holt conceded there was probably some good to be gained from Maori healing, but the benefits had not been researched.

The Health Ministry recognises and supports Maori healing practices, which include rakau rongoa (native fauna herbal preparations), mirimiri (massage) and karakia (prayer).

Massage and meditation had been proven to help people overcome illnesses, but some other therapies could actually cause harm, Prof Holt said.

"It gives them false hope and that's really a bad thing to do. We want to give them optimism in treatments that do work."

Emergency department specialist Chris Cresswell, who helped set up the service, said the alternative therapies would complement conventional treatments.

"There is good research out there that lots of alternative therapies do have a lot of good to offer. I think our society has matured and people are more open-minded."

He taught patients to meditate to de-stress and had himself used reiki and meditation.

Sixteen alternative treatment providers had agreed to offer free services on a roster basis. They were police-vetted and would go through a thorough induction when the service launched next week, Mr Taurua said.

They would not have permission to prescribe pills or potions.

He said there were a lot of issues involving ethics and informed consent to work through before patients could use the service.

He believed Whanganui would be the first hospital to have an onsite natural therapy service. A handful of district health boards had contracts with natural therapists, but did not allow them to work in hospitals. The service opens on Monday.