UN rights chief Michelle Bachelet said Monday she will not seek a second term, ending months of speculation, insisting she wanted to spend more time with her family in Chile.

Two major human rights organisations, Amnesty International and Human Rights Watch, used the opportunity to reiterate their criticism of Bachelet's stance on China.

The surprise announcement came as the 70-year-old former Chilean president opened the United Nations Human Rights Council's 50th session.

"As my term as High Commissioner draws to a close, this Council's milestone 50th session will be the last which I brief," Bachelet told the diplomats gathered in Geneva.

Speculation has been rife for months about her plans.

But Bachelet told reporters "this is not something new," saying she had informed UN Secretary General Antonio Guterres two months ago of her decision to leave "for personal reasons".

"After a long and rich career, I want to go back to my country, to my family," she said.

Guterres said in a statement he was "deeply grateful to Michelle Bachelet for her relentless service" as rights chief.

UN rights chief Michelle Bachelet had until now remained mum about whether she would seek to stay on
UN rights chief Michelle Bachelet had until now remained mum about whether she would seek to stay on AFP / Fabrice COFFRINI

Bachelet, he said, "lives and breathes human rights", and "has moved the needle in an extremely challenging political context... She has made a profound difference for people around the globe."

The post of High Commissioner for Human Rights typically faces heavy political pressure from countries around the world.

While it can be held for a maximum of two terms, nearly all of Bachelet's predecessors have avoided staying on for more than one term.

But there had been speculation that Bachelet, who has largely avoided harsh public criticism of countries, might be eyeing more time.

When Guterres appointed her in 2018, it was clear she was meant to mark a break with the repeated declarations of outrage by her very outspoken predecessor Zeid Ra'ad Al Hussein of Jordan.

Bachelet, who went from torture victim under Augusto Pinochet to become the first woman to serve as president of Chile, has instead emphasised the importance of dialogue and discreet diplomacy in forwarding rights in various countries.

Speculation had been rife for months about whether UN rights chief Michelle Bachelet would seek a second term
Speculation had been rife for months about whether UN rights chief Michelle Bachelet would seek a second term AFP / Fabrice COFFRINI

"Continue to seek dialogue," she told the council Monday as she presented an overview of human rights concerns around the world.

"Be willing to hear the other, to understand respective points of view and to actively work towards identifying common ground."

This approach has not sat well with some and she has faced significant pushback over her restraint, especially when it comes to China.

She has faced mounting criticism from countries and NGOs for not speaking out more forcefully against allegations of widespread rights abuses in the country, including during her long-awaited trip there last month -- the first in 17 years by a UN rights chief.

The criticism "has no relationship" with the decision not to take on a second term, she told journalists.

"Having been president twice, I have received a lot of criticism in my life," she pointed out. "That's not what makes me take certain positions."

Bachelet meanwhile vowed that a long-awaited report on the rights situation in the Xinjiang region, where China is alleged to have detained more than one million Uyghurs and other Muslim minorities, will be published before she steps down on August 31.

She told the council that the report was currently "being updated", and that it would "be shared with the government for factual comments before publication".

Countries and NGOs have become increasingly impatient to see that report, which they say has been ready for months.

He warned that Bachelet's focus on seeking dialogue with Chinese President Xi Jinping "lacks the pressure that alone might persuade him to ease his repression".

He urged Guterres to pick "a successor who is comfortable using the office's most important tool to improve human rights practices -- the willingness to speak out against even the most powerful human rights abusers".

"Michelle Bachelet now has just two-and-a-half months to address her failures on China," said Amnesty's Secretary General Agnes Callamard.

She urged Guterres to be "open and transparent" in choosing a successor, saying: "This important post requires a mandate holder who is principled and independent, and who has a proven record of deep commitment to human rights".

Callamard called on Bachelet to "finish her term by acting with the courage and principles that the office of High Commissioner demands".