Concern is growing on the monastic site Skellig Michael after another serious rockfall.
The island off the coast of Kerry was scheduled to re-open to visitors for the tourist season in a number of days.
Today a large boulder broke free from a slope and landed directly on the path normally taken by visitors.
The Office of Public Works says it has staff and safety contractors on site assessing the scale of the problem and that the incident may have significant consequences for the planned opening date.
The landmark has recently gained global attention after appearing in the latest Star Wars film.