Even among those women who have a pension plan, large numbers admit they have no idea how much they are contributing.
And half of the women surveyed have no idea how the tax reliefs on pension investment works, the research carried out for Friends First shows.
The findings prompted financial experts to conclude that women were now facing a pension timebomb.
One in four of all those surveyed had no idea what type, if any, pension they have. But this rises to one in three for women.
The survey reveals women are less prepared for their retirement than their male colleagues
Four out of 10 women admit they do not have a pension plan compared with three out of 10 men. Men, on the other hand, contribute more to their pensions and have better quality retirement funds. They also have a better understanding of how pensions work.
Investing in a pension is regarded as highly tax efficient. For someone on the 41pc income tax rate they can end up with €100 in pension investment for just €50 because of the way the tax reliefs work.
But four out of 10 people do not understand how the tax benefits for investing in a pension work. When it comes to women, half of them do not understand the tax reliefs for investing in a pension.
"This research indicates that there is a real inequality between the sexes when it comes to pension provision," Friends First's head of pensions Simon Hoffman said.
"Our survey reveals that women are less well-informed and therefore at a greater risk of not providing adequately for their retirement. This inequality is a cause for concern and points to a need for greater education among female workers."
Mr Hoffman said it was clear that perceived complexity remained a significant barrier to increasing private pension provision.
The recently published National Pensions Framework Strategy made a number of proposals to encourage more people to take out private pensions and to encourage people to put more into their retirement fund.
However, Mr Hoffman said there had been too many changes in the past few years, many of them making the situation worse.
"By tinkering around the edges with our pension system over the last number of decades we have created a system which alienates those who need pensions most," he added.
- Charlie Weston