Australian Slang
(interjection) 1. exclamation of surprise; 'Hey!';
2. tag used at the end of a statement in order to assure that the listener is in agreement, not necessarily requiring a reply or answer, but offering the option of agreeing or disagreeing: 'Wasn't it lucky, ay?'; 'Great fun, ay?'; 'Blessing in disguise, ay'? (The usage in def. 2 is very common, and dates back to Colonial times. It is neither restricted, nor excessively more common, to New Zealand, Queensland, or any other particular region, as often claimed)

English dialects glossary. 2013.