Yet another Australian expression of surprise, disbelief ar anguish. There is quite a collection of these (see tags below).
Usually said with each word pronounced very separately and deliberately, but is quite often uncontrolled. The first thing I said when I turned on the TV and saw the World Trade Centre collapse was:
When some resigns or retires from a job, they are on "eternity leave". This can also refer to someone who has passed away, especially someone who worked somewhere for a long time, retired/resigned, then passed away later.
Oh I'm sorry, you didn't know that Kelly is on eternity leave? She resigned and moved to Hawaii!
With regrets I would like to inform you that my boss is officially on eternity leave. I will never see or hear them again. Ever.