Ten new cases of HIV are diagnosed every week in this country.
Figures from HIV Ireland show new cases have increased by 35% since 2011.
A total of 498 people were diagnosed as living with HIV last year, compared with 372 in 2014.
The charity said the rate of increase - which is described as a "spiralling crisis" - was alarming and needed urgent action.
Executive director of HIV Ireland Niall Mulligan said: "One of the first actions of the new Government must be to address the HIV crisis in Ireland.
"HIV Ireland has been working in the areas of prevention, testing, outreach and support for almost 30 years and we are alarmed at the relentless upward trend in HIV diagnoses."
Some facts from HIV Ireland, based on provisional data from the Health Protection Surveillance Centre: