You could be forgiven for thinking it's a compost bath - but wallowing in steaming sawdust and fermented plant enzymes is the latest therapy to hit New Zealand.

It's a Japanese tradition dating back centuries, and now the enzyme bathing ritual is being introduced to Auckland by Ikoi Spa in Takapuna.

The spa owners believe the enzymes - made of a blend of rice bran, pinewood sawdust and enzyme essences from 50 fruits, vegetables, mushrooms and seaweed - can cure everything from insomnia to poor digestion as well as improving blood circulation and weight problems.

"Enzymes from the fruit and vegetable ferment within the sawdust to produce heat, and this fermentation not only provides healing qualities but is also good for the skin," said Cherry Chia, Ikoi's operations manager.


"Toxins are also released through perspiration, and the biochemical activity from the enzymes also helps with improving immune systems."

The first modern enzyme bath house was established in the 1940s in Hokkaido, and received international attention in 1972 when it was offered at the Winter Olympics in Sapporo.

On arrival, clients are given a drink of enzyme tea before being taken to a room with a giant tub of wood shavings and enzyme mix.

The heat generated by the fermenting enzymes brings the temperature to above 40C.

"It is when you are fully immersed that the enzymes start working, cleansing the body and breaking down wastes," explained Chia.

"It reduces tension and stress, while also invigorating and softening your skin."

Spa manager Ayako Kato said enzyme baths were originally for healing wounds and other ailments, but were now being widely used in Japan as a beauty treatment.

Although the baths are a ritual in Japan, Professor of Public Health Grant Schofield said he could not see any reason an enzyme bath would be much better than a regular hot spa.

"More likely, it's that it is as good as hot spa, which you think will help you," said Schofield, director of the Human Potential Centre at AUT Millennium, said.

"The placebo effect is a powerful help sometimes."