Members of an ad hoc committee, created to discuss the Welfare Reform Bill's conformity with equality requirements, expressed disappointment that the OFMDFM's equality unit had not responded to the committee's call for evidence, on 8 January 2013.
Sheila Mawhinney, the clerk of the ad hoc committee, said she had sent a reminder to the Office of the First Minister and Deputy First Minister's (OFMDFM) equality unit but had received no word back.
Sinn Fein's Mickey Brady said: "They (OFMDFM) have an equality unit and we are dealing with equality."
His party colleague Caitriona Ruane described it as "not good enough".
Ulster Unionist Robin Swann said the unit was "crucial" to the scrutiny of the Welfare Reform Bill.
The bill, if passed, will bring about the biggest shake-up of social security benefits for decades.
The changes will impact on thousands in Northern Ireland and affect disability living allowance, housing benefit and employment support.
The new legislation has already been passed in England and Wales.
The Social Development Committee had been scrutinising the bill, and the ad hoc committee was established with the aim of maximising its scrutiny and its compliance with human rights legislation.
Trevor Lunn, the ad hoc committee chairman, said the matter justified contacting the OFMDFM for explanation.