Short term to medium term, provided there is an IMF bailout, yes NTMA deposits are safe. It is totally unthinkable that the IMF will allow a restructure of NTMA debt at this stage.
Medium to long term, the irish debt needs to be restructured (the vast majority of Bloomberg investors polled agree with this statement), loans on top of loans from the IMF will not address this need. An Post deposits fund the national debt. When a restructure of national debt occurs, An Post deposits can hardly be regarded as the safest. However, a debt restructure could be 4+ years away.