After completing her PhD in Public Health in 2015, Dr Subasinghe developed a passion for improving the sexual and reproductive health of priority populations. Using epidemiological research methods, she has published over 35 peer-reviewed articles, including 15 first author publications, related to improving health outcomes for adolescents, those living with socio-economic disadvantage, and survivors of sexual abuse.

Between 2015 and 2019, her postdoctoral research at the Western Pacific WHO reference laboratory for HPV and Murdoch Children's Research Institute involved managing multiple women’s health programs in which she investigated the prevalence of reproductive health conditions in adolescent and young women. In 2017, Dr Subasinghe led a collaboration between investigators from India and Australia to pilot a cervical cancer screening program with South Indian women. To support this work, she was awarded an Endeavour Australia India Education Council Research Fellowship.

Building on her earlier epidemiological research in priority populations, Dr Subasinghe identified that she could make an important contribution to addressing healthcare inequity issues through primary health care research. In 2019, she joined the NHMRC CRE in Sexual and Reproductive Health for Women in Primary Care (SPHERE). Dr Subasinghe was CIA on a National Women’s Health Strategy funded project, EXTEND-PREFER and Chief Investigator on the MRFF-funded ORIENT Trial. In support of her research, Dr Subasinghe was awarded a Jean Hailes for Women’s Health Postdoctoral Travel Fellowship, an Advancing Women's Research Success Grant, and a place in The Oxford International Primary Care Research Leadership programme (2020-2023).

In addition to her academic commitments, in 2015, Dr Subasinghe co-founded a not-for-profit organisation, called Humanity Unearthed, to provide grassroots initiatives across the Asia Pacific with a voice and an audience.

Dr Subasinghe is currently the Preconception Health Network Research Fellow at the NHMRC CRE in Health in Preconception and Pregnancy (HiPP).