Nothing is without risk, but I’d feel this is about as close as it gets. The risk is seizure by the government, and the only way to avoid this tiny risk would be to hold something like gold personally, which faces all sorts of other risks of much greater likelihood.
Let us stick with safe meaning “unlikely to default” (there are of course other risks such as inflation). For an Irish resident State Savings are by this metric the safest instrument on the planet. Of course there is a very small probability that Ireland inc. will default or reschedule its bond obligations (conf Venezuela). But this does not imply it would default on State Savings; that would be a suicidal political call and would not in any foreseeable situation be required financially; State Savings are way less than 10% of the National Debt. Besides you would likely get good warning of that Armageddon and be able to cash out in time.
Technically, German bonds or Swiss bonds are regarded and priced as the safest instruments, but then they pay negative interest! But, say Ireland defaulted on its bonds against the wishes of the EU then it would be reasonable to expect that as a retaliatory measure the German and Swiss governments would seize Irish resident holdings of their bonds. This is really a very very unlikely scenario, but IMHO more likely than the Irish government defaulting on State Savings - which is why I say these are the safest assets on the planet for Irish residents.