It's the private bank's debts.
For some unknown reason the Irish government decided to guarantee all debts by banks in Ireland including banks that are owned and run by people who are not Irish or based in Ireland. These debts were not sovereign debts until the Irish government decided to unilaterally back them without any good cause. They did this back in 2008 and it's only now that they massive amount that they've basically handed over to private investors is becoming apparent.
I agree the guarantee was handled disastrously but I'm a little leery of the 'dirty foreigner' angle.
Which dirty foreigner private investors would these be? Bank share holders? Anyone who bought shares in the banks over the last decade has seen their investment wiped out. The Irish government owns the lion's share of Allied Irish Banks and Bank Of Ireland. Anglo Irish Bank is fully nationalised, with all shareholders completely wiped out. They gambled, they lost.
Who else then? Property developers with massive loans to the Banks that they cannot pay off? Maybe, but they are not dirty foreigners, they're home grown entrepreneurs!
Where to next? The bond markets? Dirty foreign bastards, buying Irish bonds on the promise of a coupon paid over five or ten years. The cheek of them!
Our problems are home made. Blaming the foreigners is lazy and unbecoming for a country that has sent her children to all corners of the globe. The sad thing is that because of the home grown cock up the exodus is happening again.