The draw has been made for the Olympic qualifiers in Baku Azerbaijan where Paulstowns Darren O Neill will make his Olympic bid.
He fights in the last 32 tomorrow against Mustafa El Molla of Sweden, the first of the Irish in action.
Dean Walsh, Gardiner, O’Reilly, who won European Games gold in Baku last year, and Darren carry Ireland’s hopes in Azerbaijan.
O’Reilly is the No. 1 seed in the middleweight class, while Gardiner received a bye into the last 16 at super-heavy.
Wexford light-welter Walsh received a bye into the last 32.
The top five light-welters and middleweight qualify for Rio, but heavyweights and super-heavyweights must win gold as there is just one Rio 2016 place available in both categories.
39 Olympic places are up for grabs across the ten weights in Baku.