Laya Healthcare is to increase prices on its plans by an average of 1% from 1 April.
The company blamed the rise on the "continued, unsustainable increase in the overall cost and volume of claims".
It said between 2018 and last year it had seen an 8% increase in claims volumes, while costs had risen by 6%.
Laya said improving treatments and healthcare technologies were leading to better outcomes for patients, however they are also driving associated costs higher.
The price rises form part of a review of healthcare plans by Laya, which will see some of the offered benefits change.
The company said it will extend its free cover for second and subsequent children to its Advantage 125 Explore, Advantage 125 Plus, Flex 125 Choice, Flex 125 Plus and Flex 175 Explore plans.
However it will be withdrawn from its Essential Connect Family and Essential Health 300 packages.
It will extend its health consultation service to its Assure Protect, Assure Vitality, Assure Health and Assure Ideal plans.
They will also be allowed more uses of Laya's GP Live service.
However the amount these customers will pay, per visit, to Laya's Quickcare centres will increase.
Laya said that, from 1 April, it will reduce the pricing on five schemes by an average of 2.7%.
This will include the four 'Assure' plans that are seeing changes to their benefits, and the company's Future Protect plan.