The Health Minister is insisting that the new health insurance levy will not price people out of the market.
People over the age of 34 have until April 30 to take out health insurance, or else face higher charges.
From May 1, the Lifetime Community Rating will come into effect, which will see a levy placed on those over 34 who are taking out premiums for the first time, or after a long break.
It is designed to encourage younger people to take out insurance earlier, and will amount to a 2% charge per year.
However, there will be exceptions for people who have been unemployed.
Health Minister Leo Varadkar said that encouraging younger people to take out insurance earlier will keep costs down across the board.
"This will help to keep prices down in future, because the whole idea of community rating – the way our health insurance works – is that people pay the same whether they're young and healthy or old and sick," he said.
"The only way we can sustain that system is getting people who are young and healthy into health insurance now so that we can keep prices down not just for people who are older and sicker now, but for younger people today who could be old or sick in the future."
The Minister said it was comparable to taking out a pension, where those who start paying into a pension late in life will have to pay more in order to receive the same benefit upon retirement.