Here's the thing:
* Casting is based on talent and suitability for the role. The production team will look for actors who best fit the characters, regardless of nationality.
* Irish actors have appeared in Harry Potter. Many talented Irish actors have been cast in the films, showing that it's definitely possible.
* Accents are often worked on. Even if you have a strong Irish accent, you might be able to adapt it for the role, or they might use voice coaching.
So, if you're Irish and you're a talented actor, go for it! There's no reason to think you couldn't audition for a Harry Potter movie. Just make sure you have the skills and confidence to shine!