Major health insurers have slashed some benefits, in particular for natural therapies, in response to the government's reforms to simplify health insurance.

Benefits under private health insurance are being slashed, with some policy holders paying higher premiums for less coverage, News Corp Australia reports.

It follows the government's move to simplify health cover with its Gold, Silver, Bronze and Basic reforms. Among the insurers making changes are Medibank, NIB and Bupa.

"One third to one half of health fund members will be receiving letters indicating some change. There will be inclusions as well as exclusions," Private Healthcare Australia chief Dr Rachel David said.

Many of the benefits being cut relate to natural therapies, the result of the government withdrawing the 25 per cent tax rebate. Medibank has also withdrawn some weight loss and fertility treatments.

"Anything which makes private health insurance more expensive or less value for money will continue the exodus from insurance and build up the stress on the public system to the detriment of patients on long waiting lists," Australian Medical Association president Dr Tony Bartone told News Corp.