Thousands of people who rushed to buy health insurance to avoid being hit with penalties are paying too much for their cover.
They mostly bought cheaper plans to avoid levies, but these have since sharply increased in price, making them uncompetitive, according to health insurance expert Dermot Goode.
As the fifth anniversary of lifetime community rating approaches, he said many of those who snapped up basic plans may now be overpaying by 20pc.
Some 100,000 people took out cover for the first time five years ago to avoid loadings.
Mr Goode, of TotalHealthCover.ie, said half of those who took out cover before the deadline of April 30, 2015 bought entry-level plans for themselves and their families.
From that date, 'lifetime community rating' was introduced. The system means anyone over the age of 34 who joined after May 2015 has had a loading imposed on their health insurance premium.
The loading works out at 2pc of the premium cost for every year the person is over the age of 34, if they have not had cover before.
A 44-year-old, for example, who is 10 years over the threshold, will have a 20pc loading on their premium.
Mr Goode said many of the entry-level plans bought by people to avoid the age-related penalties have jumped in price.
"People wisely took out cover in 2015 to avoid the new age loading but may now be overpaying by multiples of the 2pc loading figure," he said.
Around 50,000 of those who took out a plan to avoid loading took out an entry- level policy just to get into the system.
Mr Goode said the premiums on many of those plans have had multiple price hikes applied to them over the past five years.
Better deals are now available with almost identical cover, some of which up to 20pc cheaper.
He said people with dated entry-level plans are also missing out on new products and special deals. These include discounted offers or free cover for children.
Mr Goode said that even if the current premium on their dated plan is still affordable, the likelihood is that they might be able to upgrade their cover for the same or even a lower cost.
"Many people believe that these plans offer comprehensive health cover which is not the case at all.
"In many cases, the insurers stripped everything possible from these plans to get the price down. These plans only cover public hospitals with minimum benefits included for everything else."
Mr Goode said many Laya customers joined the Assure Vitality scheme which now costs €613 per adult and €178 per child.
However, they could now switch to a similar public-hospital-only plan called Assure Protect which will reduce their costs to €495 per adult and €151 per child.
Irish Life Health members on the Select scheme are paying €624 per adult and €209 per child.
They could switch to the equivalent Select Starter scheme from Irish Life Health which will reduce their costs to €506 per adult and €143 per child.
VHI members may be less likely to be over-paying on the entry-level plans as the insurer has removed or upgraded many plans at this level, Mr Goode pointed out.