STP Reporting - necessary for contractors (classed/processed as employees)

Does STP reporting need to be done for contractors classed as employees? We process contractor Invoices through payroll so that the Super is calculated/collated but are we meant to also report through STP? I can't seem to find any information about this.

FYI, we report the contractor payment details through the annual contractor reporting in the business' online ATO portal

Many thanks, Lee