The National Women's Council is warning that new mothers will be left out of pocket following the introduction of a tax on maternity benefits.
The cut to the payment was announced last December by Finance Minister Michael Noonan.
The tax - which came into effect on Monday - will see benefits for working mothers reduced by up to €103 a week or €2,700 a year.
Policy worker with the National Women’s Council Anne Irwin said many women aren't aware of the cut.
"A lot of new mothers are going to out of pocket quite considerably," she said.
"This was first announced in the Budget last year but I think it's only now that people are beginning to wake up - it could well be when new mothers receive their next pay packet that they will actually realise the impact that this is going to have on them."