Dr Sia Peng Ong


Dr Ong is a Gastroenterologist at Pennant Hills Gastroenterology since 2008.   She is also a staff specialist at Hornsby Hospital since 2005.  She is the current Chair of the Section of Physicians at Hornsby Hospital and is the Head of Department of Gastroenterology since 2015. 

Dr Ong is a member of the National Examining Panel – Adult Medicine for the Royal Australasian College of Physicians since 2017.  She previously held the position of Director of Physician Training at Hornsby Hospital from 2008 to 2015.  

She is actively involved in the clinical teaching of medical students from the University of Sydney.  She also provides mentorship for Junior Medical Officers at Hornsby Hospital as part of the Network 6 Mentorship Program. 

Dr Ong prides herself in providing the best possible care for all her patients. 

  • MBBS (Hons)
  • FRACP 
  • MRCP (UK) 
  • General Gastroenterology and Hepatology (in particular viral hepatitis)
  • Accreditation in Gastroscopy and Colonoscopy by Conjoint Committee for Recognition of training in Gastrointestinal Endoscopy
Professional Membership
  • Gastroenterological Society of Australia (GESA)
  • Australian Medical Association (AMA)
Current Appointments and Visiting Rights
  • Pennant Hills Day Surgery
  • Hornsby Ku-ring-gai Hospital