Just 27% of Irish companies say they have a gender pay gap.
A new law to address the issue is to be discussed at Oireachtas Justice Committee today.
Under the proposals, companies will have to publish the difference between what they pay their male and female employees.
If a company is found to have a gender pay gap, they will have to outline how they are going to address it.
CEO of CIPD Ireland Mary Connaughton said the proposed legislation is not clear enough:
Ms Connaughton said: "We don't have clarity about what's meant by pay, so companies will be asked to report the average pay of men and the average pay of women on an hourly basis.
"But does that include shift allowance, does it include overtime? How is that to be actually calculated?"