First instance body dealing with electoral disputes
Ireland
Answer
Court of general jurisdiction (including Supreme Court)
Source
http://www.irishstatutebook.ie/1993/en/act/pub/0028/print.html
Presidentialelections act, 1993
24.—(1) Where at theruling on nominations a person purported to be nominated as a candidate at theelection concerned or the authorized representative of such a person objects,on grounds which shall be stated there and then, to—
(a) the ruling by the presidential returning officer onthe validity of any nomination, or
(b) the eligibility for election to the office ofPresident of any person declared to stand nominated as a candidate at thepresidential election concerned, and states that it is intended to appeal tothe High Court against the ruling or declaration, the presidential returningofficer shall adjourn the ruling on nominations until such time after theappeal is finally determined or withdrawn as the presidential returning officermay fix or, if such an appeal is not instituted within the period of 2 daysfrom the date of the adjournment, until the expiration of that period.