UN Secretary-General Antonio Guterres is set to appoint Michelle Bachelet, Chiles twice-serving president who endured torture under the Pinochet regime, as the world bodys new human rights chief, diplomats said Wednesday.

Bachelet, 66, would replace Zeid Ra'ad Al Hussein of Jordan, a sharp critic of US President Donald Trump's policies, who held the post of UN high commissioner for human rights since September 2014.

A two-time president who ranks among the world's most powerful women in politics, Bachelet also served in 2010 as the first director of UN Women, the UN agency promoting gender equality worldwide.

Diplomats said UN Deputy Secretary General Amina Mohammed told a meeting of ambassadors this week that Bachelet had agreed to take on the role of UN human rights boss.

The diplomats cautioned, however, that her appointment must be endorsed by the General Assembly.

UN spokesman Farhan Haq declined to confirm the decision but said a name was being sent to the 193-nation assembly. "The process is nearing its conclusion," he said.

Bachelet would step into a position that has drawn much controversy under Zeid, who decided not to seek a second term after losing support from powerful countries.

After clashing with the United States, Russia and China, Zeid decided to bow out, telling staff in a message that "in the current geopolitical context," to stay "might involve bending a knee in supplication."

During a farewell news conference last week, Zeid defended his no-holds-barred approach.

"Silence does not earn you any respect," he said as he prepares to step down on August 31.

Zeid said his advice to his successor would be to "be fair and don't discriminate against any country" and "just come out swinging."

One of the world's most difficult jobs

With Zeid under fire during his tenure, rights groups had expressed concern that Guterres would seek to appoint a less vocal human rights chief.

"If selected, Bachelet will be taking on one of the world's most difficult jobs at a moment when human rights are under widespread attack," said Human Rights Watch executive director Kenneth Roth.

"As a victim herself, she brings a unique perspective to the role on the importance of a vigorous defense of human rights. People worldwide will depend on her to be a public and forceful champion, especially where offenders are powerful."

The daughter of a general who opposed Augusto Pinochet's overthrow of president Salvador Allende, Bachelet was detained in 1975 and held for several weeks at the infamous Villa Grimaldi interrogation and torture centre in Santiago.

"I was mainly tortured psychologically, and some beating, but they didn't 'grill' me," Bachelet said in an interview, using prisoners' slang for electric shocks administered to detainees.

"I was lucky compared to so many others. Many of them died," said Bachelet in the 2014 interview, one of the few times that she has discussed the ordeal.

The pediatrician and socialist who was Chile's first woman to hold the presidency was in office from 2006 to 2010 and again from 2014 to 2018.

Last year, Guterres appointed her to be on a high-level UN panel on mediation that provides him with advice on UN peace efforts.

The UN chief described her as a "long-time champion of women's rights" with a "history of dynamic global leadership, highly-honed political skills and a recognized ability to create consensus."

Born in Santiago, Bachelet was studying medicine when she was detained for several weeks. After her release, she went into exile with her mother to Australia and then moved to East Germany.

Bachelet returned to Chile in 1979, but was prevented from working as a doctor for political reasons. She continued studying, specializing in pediatrics and public health.

After democracy was restored to Chile in 1990, she worked for the health ministry and in 2000 was appointed health minister followed by defense minister four years later.

As president, Bachelet offered a dramatic break from Chile's highly conservative political class. She reformed the pension system and improved health and social services, focusing on Chile's working poor.