"Men At Work" and "Land Down Under".
1) This is an absolutely cracking pop song. Amazingly good.
2) It is only very vaguely like "Cookaburra Tree" or whatever it's called.
3) Even if it is partly based on "Cookaburra" - so what? All artists borrow and re-interpret!
4) Fundamentally "Land Down Under" is NOT the same thing as "Cookaburra".
They are different pieces of work!
5) Copyright of any kind is unworkable rubbish anyway. If you create it - you share it.