More than 60 non-governmental organizations, including Amnesty International, Human Rights Watch and the International Federation for Human Rights, have sent an open letter to United Nations Secretary-General Antonio Guterres about what they expect in the next high commissioner for human rights.
The groups are displeased with the current UN rights official, Michelle Bachelet.
The NGOs insisted that the position of UN rights chief was "critical... particularly at a time when human rights standards and mechanisms face enormous pressure from powerful governments".
The post "requires a human rights champion who is courageous and principled," they said.
The groups said the appointment should be "open, transparent and merit-based," that it should involve consultations with independent rights organizations and activists.
They insisted it was "imperative that this process move quickly".
The groups emphasized the sort of candidate they would like to see, hinting they would prefer a break with Bachelet's discreet, diplomatic style.
"The high commissioner's role is to be the world's leading human rights advocate, as distinct from the role of a diplomat or political envoy," they wrote.
"Demonstrating solidarity with victims and publicly calling out abuses should take precedence over friendly dialogue with governments."
Bachelet, the first woman president of Chile, has faced significant pushback over her restraint, especially on China.
She faced significant criticism for not speaking out more forcefully against allegations of widespread rights abuses in the country, including during her trip there last month -- the first in 17 years by a UN rights chief.
And she has faced pressure to release a long-delayed report on the situation in the Xinjiang region, where Beijing stands accused of detaining more than one million Uyghurs and other Muslim minorities -- charges it vehemently denies.
She has vowed the report will be released before she steps down.
The post will open August 31 with Bachelet's departure. She made the surprise announcement last week that she would not stand for a second four-year term.
The General Assembly, which created the high commissioner position in 1993, determined that the rights chief appointments should be conducted "with due regard to geographical rotation".
This principle has not been fully respected in the past, with several of Bachelet's predecessors coming from Latin America.
The only region that has yet to boast a high commissioner is the Eastern European region, which includes Russia.
But so far there has been no indication from Guterres on who he has in mind to fill the position.