what acsent has shrek got?

I believe he is supposed to be Scottish.

thankyou boomerang it sounds obvious now i know, oh well

According to my information it was Mike Myers' impression of an Irish accent (at least in the first film, haven't seen the second one yet)

Must be the Irish accent from one of those little black islands off the coast where they haven't talked to someone from Dublin in a hundred years.

Irish accents vary. There is no truer statement than that. Put an Orangeman on a barstool next to a Kerryman and if they stop plucking the eyes out of each other sockets for a moment to speak you can hear the tremendous difference.

Northerners speak fast and there's a flatness, an atonalness to the sound. Southwesterners (Kerry Dingle) speak fast enough, faster than Americans I mean, and there is more lilt to the rhythmn of the phrasing especially if there's been a round or two served.