Under the Superannuation Industry (Supervision) Act 1993, your superannuation fund is authorised to collect your TFN, which will only be used for lawful purposes.
These purposes may change in the future as a result of legislative change.
The trustee of your superannuation fund may disclose your TFN to another superannuation provider, when your benefits are being transferred, unless you request the trustee of your superannuation fund in writing that your TFN not be disclosed to any other superannuation provider.
It is not an offence not to quote your TFN. However giving your TFN to your superannuation fund will have the following advantages (which may not otherwise apply):
your superannuation fund will be able to accept all types of contributions to your account/s (as applicable);
the tax on contributions to your superannuation account/s will not increase;
other than the tax that may ordinarily apply, no additional tax will be deducted when you start drawing down your superannuation benefits; and
it will make it much easier to trace different superannuation accounts in your name so that you receive all your superannuation benefits when you retire.