Several robotic surgical systems have been developed for minimally-invasive surgery including commercialized products such as da Vinci and ZEUS. We have developed a minimally-invasive surgical system, which had performed remote surgery experiments for four times until now (performed on pigs over 150 km in Japan). In this paper, two approaches that extend the system from the perspective of extensions of surgeon's dexterity are described. The first approach is a development of complex robotic forceps, which have multiple d.o.f. on their tip. A complex rigid link mechanism has been applied to the robotic forceps to realize 3 d.o.f. motions in a patient's abdominal cavity. With the rigid link mechanism, surgeons have no longer need to be concerned a cable cutting problem, which often can be happened on conventional cable driven systems. The second approach is a force feedback capability. The developed rigid link mechanism is preferable for an implementation of a force feedback capability. The force feedback capability is important not only for extending surgeon's dexterity but also for preventing unexpected damage on internal organs. An evaluation experiment of the force feedback capability on a simulated surgical procedure was conducted. An augmented force presentation method was developed that displays contact information between forceps and soft tissues. In an evaluation experiment, the load applied to soft organ tissues was reduced by approximately 30% compared with a conventional force feedback method.