The reference number arrives the moment you submit your TFN application, and it is the evidence that the application is in progress. That evidence is what keeps you on the working holiday maker rate of 15% during the 28 day window instead of 45%.
What is the reference number and where does it come from?
It appears on the confirmation screen at the end of the online application and is sent to the email address you gave. It is a tracking number for the application rather than an identifier for you, and it looks nothing like the nine digit TFN that follows.
Think of it as a receipt. It proves the application exists, it lets the ATO find that application instantly if you have to call, and an employer can point to it when asked why a new starter has no TFN on file.
What does it actually do for your pay?
It supports the answer you give on the Tax File Number Declaration. That form has a box for recording that you have applied for a TFN but not yet received it, and an employer with that recorded applies the working holiday maker rate through the 28 day window rather than the 45% no TFN rate.
The declaration changes the rate. The reference number is the evidence that the declaration is honest, and a payroll office that has never seen one will want to see it.
What can it not do?
Three things, each a regular mistake because the reference number looks official enough to be taken for the real one.
It does not go in the TFN field on any form. A reference number typed into a payroll system as a TFN produces a mismatch that has to be unwound later.
It cannot be used to lodge a tax return. Only the real number can.
It cannot be given to a super fund in place of a TFN. A fund without your TFN taxes contributions at a higher rate and struggles to match the account back to you when you claim it, one of the main reasons backpacker super gets lost.
How long until the real number arrives?
Up to 28 days is the ATO's stated ceiling and about two weeks is typical. It arrives as a letter posted to the Australian address on your application, and only as a letter.
The reference number stops mattering the day the letter arrives. Until then, keep the confirmation email, because it is what you will need if the 28 days pass and nothing has come.
What do you do when the TFN arrives?
Give it to every employer with an updated declaration, not just the current one. Each employer holds its own record, so the packing shed knowing your TFN does nothing for the pub.
From that point the correct rate applies going forward. Anything withheld above 15% before the number was on file is not corrected in payroll and comes back through your return instead.
Is the reference number any use to you?
It does the same job for everyone, but whether it matters depends on what you are doing during the wait.
- Whether you are working during the wait at all. If you are not, none of this costs anything.
- Whether the declaration records the in progress application.
- Whether your employer accepts it. Larger hospitality groups and labour hire firms handle this routinely; small single site operators sometimes apply 45% regardless, which is their right and is recoverable.
- Whether the address on the application will still hold your mail in a month.
- Whether you have held an Australian TFN before, in which case the task is retrieving the old number.
Anything withheld above the correct rate comes back through your working holiday tax return, and you can estimate your tax refund once you know how long the gap ran.