In an annual appeal for voluntary contributions from countries and private donors, UN High Commissioner for Human Rights Volker Turk said his office would need $452 million this year.
"Without human rights there can be no enduring peace," he said at the appeal launch.
"No sustainable development. No justice."
The UN rights office teams monitor situations around the world, collect data on abuses and provide guidance to countries and technical backing for implementing better human rights standards, and support for civil society.
Last year, donors provided the UN rights office with $240.8 million, only covering 60 percent of the amount requested.
While thanking those who provided funding, Turk warned that that shortfall had impacted the work the office was able to carry out at a time when it is being asked to do more than ever.
In 2022, its advisors provided "essential guidance" in 50 nations, Turk pointed out, adding that the office currently had requests to send such advisors to six additional countries.
"But we need additional financial support to be able to provide this help," he said.
"Unless more funds can be found, we will instead need to cut our deployment of human rights advisers in 2023, from 50 to 43 countries."
Turk said he hoped the 75th anniversary of the Universal Declaration of Human Rights coming up at the end of the year would encourage an increase in funding.
"Now, more than ever, we need human rights to keep the world stable and provide us a roadmap to a better future," he said.
"We need to insist on action, globally and domestically, that addresses inequalities, strengthens social protections, and eliminates discrimination and other root causes of conflict, environmental crises and misery," he said.