Network nodes and methods for control thereof for dynamic network slice selection. An AMF receives a UE request originating from the UE, the UE request being any one of a registration request and a session request. A network slice requester controls a transmitter to transmit a network slice selection request to a PC_NSS. A selection data manager of the PC_NSS determines selection data specifying one or more UE specific parameters affecting network slice selection. A network slice selector selects a network slice assignable for the UE, based on the selection data, determines network slice data and a corresponding network slice routing rule, and transmits them to the AMF. A network slice manager of the AMF controls assignment of a network slice to the UE in dependence on the received network slice data and network slice routing rule.