It happen to me too, the network provider will help you with the puk number.
Here are some network providers and tel numbers:
02 Ireland: 1850 60 17 47
Vodafone: 1850 20 87 87
Meteor: 1800 36 50 85.
3 Mobile: 1913 (free from any Irish landline)
Tesco
Mobile: 089 420 0000