In the first place, do you have sub contractors? Do you have sub contractor agreements (SCA) in place? It is imperative as you can easily be seen as an employer. That means you may have to pay superannuation, work cover entitlements, holiday pay and long service leave commitments.
Finally, refer our video attached below as getting this wrong can leave you severely impacted and the ATO will have no leniency if no legitimate sub contractor agreements are in place.