A method for resource object level authorization at a network function (NF) includes maintaining, by a first NF, a service based interface (SBI) resource object access authorization policy database containing policies for controlling access to SBI resource objects and dynamically populating a resource object owner database containing records for resource objects and corresponding resource object owners. The method further includes receiving, by the first NF and from a second NF, a first SBI resource object access request for accessing a resource object, accessing, using information from the first SBI resource object access request, the resource object access authorization policy database and the resource object owner database, determining that an access to the resource object requested by the first resource object access request is not permitted, and preventing the access to the resource object requested by the first resource object access request.