A review group set up last November to address the problem of pyrite in homes has yet to begin its work - despite having a deadline of reporting by the end of May.
In November, Minister of State Paudie Coffey announced the establishment of an expert panel to investigate serious problems with pyrite and mica in block work in hundreds of homes in Donegal and Mayo.
This followed revelations that several hundred homes in those counties were crumbling due to deficiencies in concrete.
Homeowners have been left with crumbling and increasingly dangerous houses, which are now virtually worthless.
In the rural Erris area of Co Mayo, 100 homes have so far been impacted by pyrite problems, with fears that the number could double.
The expert group was tasked with identifying the number of private dwellings which appear to be affected by defects in the block work.
When the group was announced four months ago, Mr Coffey, Minister with Responsibility for Housing, Planning and Co-ordination of the Construction 2020 Strategy, said he was "acutely aware of the extremely difficult and distressing situations that affected homeowners in Donegal and Mayo are facing on account of damage to the structural integrity of their homes".
However, while the group is due to submit a report to the Minister of State by May 31, to date only one person has been appointed.
In January, a former director of services with Waterford County Council, Denis McCarthy, was appointed to chair the panel. The remaining members of the group have yet to be appointed.
A spokesperson for the Department of Environment said: "Nominations are currently being sought from a number of professional bodies (i.e. Engineers Ireland, the Institute of Geologists of Ireland and the National Standards Authority of Ireland) for suitable persons to participate in the group, which it is envisaged will be comprised of technical experts.
"It is anticipated that all three nominees will be received in the department shortly and that the expert group will commence its investigations into the matter at the earliest opportunity thereafter."
The group is due to carry out a consultation process with affected homeowners, public representatives, local authorities, product manufacturers, building professionals, testing laboratories, industry stakeholders and other relevant parties in an attempt to establish the nature of the problem.
It will then outline a range of options for remediation and how these options could be applied.
Problems with concrete blocks in north Donegal and Mayo first came to the attention of the department in late 2013. Impurities, such as muscovite mica and pyrite, have been identified as elements within some of the affected blocks.