In just over two weeks' time, they will have earned as much in the previous 17 months as their male counterparts earned in 2005. An Irish male worker on the industrial wage earned just over 31,000 last year, according to figures from the Central Statistics' Office. A female earned slightly more than 22,400. To match the shortfall, a female worker would have to work 22 more weeks than her male counterpart.

The disparity in pay packets alarms the National Women's Council of Ireland.

"The reasons for the gender pay gap haven't been addressed, " said the National Women's Council of Ireland's head of policy and practice, Orla O'Connor.

She added that women taking time off work to mind children are returning to the workplace, but doing so on lower wages and with lower status than they would have held previously. O'Connor said that that the gap is "worrying" considering the strength of the economy and said the position was at odds with the government's aim of enticing more women back into the workplace. She argued that addressing the inequality in pay could at least be partly achieved by directly subsidising childcare to a greater extent and also introducing paid paternal leave that would encourage men to take time off work in the initial months following a birth.

The pay gap has improved slightly since 1998, when women on the industrial wage had to work over 26 weeks extra to generate the same income as their male counterparts.

Similar problems exist in other developed countries.

In the US, equal pay day fell two weeks ago. US women earn, on average, 77% of the male wage, according to figures compiled by economist and former lieutenant governor of Massachusetts Evelyn Murphy.