A decision is expected today on whether Skellig Michael will be open to visitors this weekend following a rockfall on the island on Monday.
The Office of Public Works was advised of a further serious rockfall at the UNESCO World Heritage site after a large boulder broke free from the slope above Lighthouse Road.
The boulder effectively blocked the pathway taken by visitors accessing the base of the South Steps leading to the 6th century monastic settlement.
The OPW said the rockfall was deeply worrying and indicated the upper slopes on the island remain highly unstable and unsafe.
OPW staff and a safety officer have been assessing the scale of the problem and a decision on its reopening is expected to be made today.