The Irish Family Planning Association is calling on the government to implement a national sexual health programme.
It has published data from an online STI testing service it runs in partnership with Lloyds Pharmacy.
The service allows people to send samples away for testing for infections including Chlamydia, Gonorrhoea and HIV.
Last year almost one thousand Irish people used the service - 57% of them were women.
However, fewer women than men asked for HIV testing.
"Interestingly enough, I the UK, more men than women use our service. In Ireland, it's more women," said Doctor Tom Brett from Lloyds.
"That may be because the other services we offer … are tailored more for women, in terms of contraception.
"[But] in terms of positive [results], they are quite similar to what we see in the UK."