Kolkata, June 23 (IANS): Nepal Prime Minister Sushil Koirala on Tuesday condoled the death of Sister Nirmala, who had roots in the neighbouring Himalayan country, saying the world has lost a "great humanist social worker" with her death.

Sister Nirmala, who succeeded Mother Teresa as superior general of the Missionaries of Charity, died here on Tuesday. She was 81.

"With the demise of Sister Nirmala, the world has lost a great humanist social worker. I express my heartfelt condolences," Koirala tweeted.

The Nepalese Consulate in Kolkata extended condolences to the organization.

"At this hour of pain, we express our heartfelt condolence and pray to the almighty God to give the bereaved members of MoC and the Nepalese communities living in Nepal, India and other countries, the strength to bear this unbearable and irreversible loss," Consul-General Chandra Kumar Ghimire said in a message.

Nirmala was born Nirmala Joshi in Ranchi to a Brahmin family from Nepal in 1934.