Four out of 10 families may see their child benefit cut under new proposals being considered by the Minister for Social Protection.
A government-appointed advisory group is recommending a "two-tier" child benefit system, with only those earning less than €25,000 automatically receiving a full payment.
The model uses the example of a basic payment of €25 per week rising to €63 per week, depending on income levels.
Chair of the advisory group Ita Mangan said middle-income families would be most affected.
"All higher-income people would also lose under the proposal," she said.
"However, the loss to them is not as proportionate as to lower income groups. In other words, it doesn't matter quite as much to higher-income groups as it does to middle-income groups."