Dr Noeleen Heyzer, 66, is best known for putting Singapore on the United Nations (UN) map.

In 1994, she became the first Singaporean to head a UN agency, the United Nations Development Fund for Women (Unifem), which gives aid to improve women's lives in more than 100 countries.

In her 13 years as the Unifem chief, she was credited with putting issues affecting women high on the UN agenda, significantly increasing its budget and improving its programmes.

In 2007, she became the first woman to head the UN Economic and Social Commission for Asia and the Pacific (Unescap), the UN's regional development arm.

She was said to have strengthened its capacity and effectiveness in engaging and supporting the Asia-Pacific countries in economic and social growth.

Now, the UN veteran of almost 25 years is the special adviser to the UN chief for Timor Leste, to support the country's nation-building after 25 years of being occupied by its neighbour Indonesia.

Her husband, former Malaysian Member of Parliament and social activist Fan Yew Teng, died in 2010 of cancer. She has twin daughters who are in their 30s.

Born to a Eurasian father and a Chinese mother, she was six when her mum. Her dad remarried and she was brought up by her grandmother, a widow who was uneducated but who stressed the importance of education.

Coming from an "extremely poor" background, Dr Heyzer said in an interview: "There were circumstances that made me a leader because I saw so many things falling apart as a child, both within the country and at home.

"I found that either I took leadership and found solutions, or things would get worse or wouldn't get done."

She received her Bachelor of Arts and Masters of Science from the then University of Singapore and a PhD in sociology from Cambridge University.

She worked in banking for less than a year, found it unsuitable, and her "outrage over human suffering and injustice" propelled her into development work, she said in interviews.

Among her proudest professional achievements, she told The Sunday Times, was to get the UN Security Council to look beyond maintaining international peace to also focus on how war affects women, such as rape being used as a wea- pon of war, and to stop the abuse.

With the Security Council implementing the landmark Resolution 1325 on Women, Peace and Security, this paved the way for women to participate in peace negotiation and the electoral process and to help shape their post-conflict societies.

She said the landmark resolution led to equal inheritance laws in Burundi in east-central Africa, women being given full citizenship rights in Afghanistan and more women entering politics in countries such as Rwanda and Liberia, among other things.

As Unescap head, she worked closely with Asean and the Myanmar government to assist in recovery efforts after Cyclone Nargis ravaged Myanmar in 2008.

After that, she was able to win the trust of Myanmar's leaders and initiate dialogue between international scholars, such as Nobel Prize economist Joseph Stiglitz, and

Myanmar government agencies to help develop the country.

She has been recognised as helping to catalyse the opening up of Myanmar.

Ambassador-at-Large Tommy Koh said Dr Heyzer has "invigorated" Unescap, "bringing a new vision, energy and relevance" to the organisation.

He added: "Singaporeans of both genders ought to know more about Noeleen Heyzer and admire her good work. She was an eloquent champion of women's rights."

Dr Heyzer said she was most moved when member states of the UN gave her a standing ovation when she stepped down from the UNESCAP recently.

Dr Heyzer, who has lived overseas for more than 30 years and is now based in Bangkok, said: "Eventually, I plan to come back to Singapore."

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