The biggest barrier to family planning is the high cost of contraception, according to the National Women's Council of Ireland.
It is calling for all forms of contraception to be made available free of charge in its pre-budget submission.
Just 19% of women of reproductive age use implant devices like the intrauterine coil.
Cliona Loughnane from the council says Ireland is unusual by not making these methods free.
"In most European countries, contraception is considered a core part of healthcare provision," said Ms Loughnane.
"When you look in the Irish context, unfortunately, while most people in reproductive health are using some form of contraception use still seems to be quite inconsistent."
Health Minister Simon Harris said ahead of the referendum on abortion that he was aiming to address the cost of contraception this year.
"We need to ensure that women can access all forms of evidence-based contraception," said Ms Loughnane.
"It was a promise that was made to women as part of the referendum process and we know it's something that the Department of Health are currently looking at.
"We need to make sure that the funding is there in 2020 to provide it."