Weird question, that I'm not too sure who to ask. But since I started this new job June 12th, do I need to lodge a tax return for that period of 18 days at my job?
I'll still need to do one since I worked at a convention last year, but just wondering what the procedure is regarding this new job...
The tax is based on when you were actually paid, not the year the work was done in. So if you didn't get paid before the end of the financial year you don't need to worry about it.
If you were paid this financial year then you will claim that next year, if you log in to mygov at the end of July your payment statements should be there
Are you on a wage (employee), or a rolling contract (consultant)? If you're on a wage, then yes, you need to treat those days as being last financial year. If you're on a rolling contract, you treat the entire month as being in the financial year when the invoice is issued.