The ATO guidelines doc is 33 pages in pdf, but here are the key bits.
Under “Voluntary reporting” (page 13) it says:
You can also choose to include reportable employer superannuation contributions (RESC) …for your employees. If you choose to include these amounts in a report by 14 July in the next financial year and complete a finalisation declaration you are not obliged to give payment summaries and a payment summary annual report to the Commissioner of Taxation covering these amounts.
If you choose not to report these amounts through STP, you will be required to give payment summaries to your employees and a payment summary annual report to the Commissioner covering these amounts.
Under “Reportable employer superannuation contributions” (page 23) it says: