Teaching training and examining students and staff has been a main focus and interest of Dr Amarasekera. Initially, He worked as a lecturer at the faculty of medicine, University of Colombo. Then as a research and teaching fellow at the University of Warwick School of Medicine, UK for over 10 years. He is currently a Visiting Senior Lecturer in the faculty of Medicine, University of Kelaniya, and Kotalawela Defence University (KDU). He serves as an undergraduate examiner for the University of Warwick, University of Kelaniya, and KDU. 

He also examines ERPM students. At present, he works as a trainer in NTMC course (National Trauma Management Course) and AO and AO Alliance (Association of Orthopaedics) Basic and advance courses. He currently serves as a reviewer for bona and joint journal ( formerly JBJS ) UK and is a member of the editorial board, Sri Lanka Journal of Surgery and Editor of SLOA Journal (Journal of Sri Lanka Orthopaedic Association)