Mr Chan (22), who attended Wellington College, is graduating with an MBChB from the university today, and recently began working as a house officer at Dunedin Hospital.
Miss Chan (24), who attended Wellington Girls' College, will gain an MSc in microbiology.
He had greatly appreciated having another family member living in Dunedin while he was undertaking his medical studies, Mr Chan said.
He had enjoyed visiting his sister's flat to share her home cooking, including steamed fish and rice dishes, and one particularly memorable chocolate cake.
He was also looking forward to graduating with his sister, and having his parents and brother Dr Calvin Chan, another Otago medical graduate, in Dunedin for the celebrations.
Bringing the whole family together meant ''a lot more fun'', he said.
Miss Chan said that she had ''really enjoyed'' undertaking her microbiology research project, and had appreciated the ''challenging but really supportive'' community in the microbiology and immunology department.
Her project involved scientific testing linked to a squid gel earlier developed in the Otago chemistry department for use in reducing postoperative complications after nasal surgery.
The gel is already being used successfully, and the further Otago research is linked to the idea of potentially extending use of the gel to help avoid complications after stomach surgery.
Dr Heather Brooks, a senior lecturer in microbiology, co-supervised Miss Chan's research with Dr Jaydee Cabral, of the chemistry department.
Miss Chan's research had made a ''very useful'' contribution, Dr Brooks said.
