VHI Healthcare is to increase its prices by between 6% and 12.5% from the start of next month.
The insurer said the increases are due to rising customer claims costs.
The average increase is 9%.
VHI Chief Executive Declan Moran said its private health insurance business is currently loss-making.
Minister for Health James Reilly has said he is disappointed with the VHI price rise.
Dr Reilly said that a meeting of the Health Insurance Forum will be convened in the next few weeks to address the costs of medical care in the private sector.
The increase for the VHI's most popular plan, the OnePlus plan, will see the current annual premium for two adults and two children rising from €2,093 to €2,250.
VHI said it spent €1.2bn in funding its customers' health needs last year and added that it has made savings of over €190m since 2009.
Mr Moran said: "We are acutely aware of the enormous financial pressures facing our customers and have endeavoured to keep the price increases on our plans as low as possible.
"Today's price increase is the lowest possible amount we could introduce to ensure we can meet the cost of our customers' healthcare needs in 2012."
The announcement is the latest in a number of increases in plans by private health insurers.
Aviva Health plans are increasing by 15% next month and Quinn Insurance plans go up by 6% also next month.
The last general VHI price increase in February 2011 ranged from 21% to 45%.
