Improved techniques for secure access control in communication systems are provided. Secure access control in one or more examples includes authorization of network function sets. For example, in accordance with an authorization server function, a method includes receiving a request from a service consumer in a communication system for access to a service type, wherein the request comprises information including a service producer set identifier. The method determines whether the service consumer is authorized to access the service type. The method identifies service producer instances that belong to the requested service producer set identifier. The method generates an access token that comprises identifiers for identified ones of the service producer instances that belong to the requested service producer set identifier, and sends the access token to the service consumer.