Zulkhairy has been with the national team setup since 2012, when he was chosen to represent Brunei at the 40th Asian Schools Football Championship for Under-18s that year. His first appearance for Brunei under-23s came at a friendly against Indonesia at Maguwoharjo Stadium on 15 August 2013. He competed at the 27th SEA Games, appearing once as a substitute against Laos in a 3–2 loss.