Hnilička played his first game for the Czechoslovak junior team in 1990 at the 1990 European Junior Championships, winning a bronze medal. He played again for the Czechoslovakian junior team at the 1991 World Junior Championships, again winning bronze. He was named to the Czechoslovakian senior team for both the 1991 Canada Cup and 1991 World Championships, but did not play in either tournament. Hnilička's final tournament for Czechoslovakia was the 1992 World Junior Championships, where the team finished fifth.