More than 206,000 Irishmen enlisted in the British army during the four-year conflict, and about 40,000 of them were killed.
British ambassador Dominick Chilcott said that joint commemorations could be held at battlefields and war memorials to remember the event.
Many Irishmen perished in the attempt to take Gallipoli from the Ottoman Turks in 1915 and two divisions were cut to pieces the following year at the Battle of the Somme.
About 58,000 were already enlisted in the British army and navy before the war broke out and thousands more joined up from Ulster, Leinster, and Munster, and to a lesser extent Connacht.
The ambassador said a “debt of gratitude” was owed by Britain to the Irish troops who had fought in the war.
He made the comments yesterday after delivering a lecture at UCC on the Third Home Rule Bill crisis of 1912-14.
The ambassador said it was hard to read about those times without coming away with a strong admiration for John Redmond, who encouraged Irishmen to enlist.
“Redmond realised that this was not a war of two morally equivalent parties, as some have presented it. There was an aggressor and at least one neutral victim — a small Catholic country, Belgium. It was the violation of Belgium’s neutrality, of course, that triggered Britain’s entry into the war.
“His aim was to persuade Ulster Unionists voluntarily to come in under a Home Rule government in Dublin. His goal was ‘unity by consent’. He hoped that the experience of fighting shoulder to shoulder would bind together Ulster Unionists and Irish nationalists. It didn’t work, as we know.”