VHI Healthcare is cutting fees paid to hospital consultants and GPs by 5% from tomorrow.
The country's biggest health insurer is making the move to save costs and keep subscriptions increases down.
The measure is expected to save around €15m euro a year.
VHI Healthcare pays out over €1bn a year on claims for subscribers and reported a deficit last year of €65m.
New contracts implementing the changes have been issued today to doctors, who will individually have to decide whether to accept the reduced fees.
VHI has also asked the Government to cut the charges for private beds in public hospitals.
They are set by the Department of Health and can be as high as €910 a day.
It says that some of the bed charges in public hospitals now exceed charges applied by private hospitals by 11%.
The insurer is also urging customers to scrutinise statements they receive after care, given that around 2,500 queries on bills from hospitals and doctors now arise each year.
Since 2005, over €2m has been recouped due to overcharging on treatments, tests or accommodation.
