She is a member of the Democratic People’s Movement in Sri Lanka, which is a coalition of people’s movements, NGOs and trade unions initiating action and dialogue for alternative development paradigms. She is President of the International Movement Against All Forms of Discrimination and Racism (IMADR) and the Women’s Forum for Peace in Sri Lanka. Nimalka is a founding member of Asian Regional Exchange for New Alternatives or ARENA and was a member of the ARENA Executive Board 1994 – 1997.