Fianna Fáil says the addition of an extra 37,000 homes to the National Broadband Plan shows how "disorganised and haphazard" it is.
The homes in Dublin, Galway, Wexford and Cork will now be provided with high-speed broadband by the state after a commercial operator pulled out.
EU state aid rules previously prevented government from taking on the homes.
But Fianna Fáil's communications spokesperson, Jack Chambers, says the plan is clearly flawed:
