SIPTU is calling on the Government to take action to minimise differences in pay between men and women in Ireland.
The union has published a list of key recommendations - the move coincides with European Equal Pay Day.
The average hourly rate for women is 16.3 percent less than men, which is the equivalent of women working for free for the rest of the year while men continue to be paid.
SIPTU is recommending stronger systems of collective bargaining and gender neutral parental policies.
SIPTU Economist, Marie Sherlock, says the union is also calling for mandatory pay reporting within companies.