Zimbabwe president Robert Mugabe has long faced United States sanctions over his government's human rights abuses.
However, the World Health Organisation's new chief is making the long-time African leader a "goodwill ambassador."
With Mr Mugabe on hand, WHO director-general Tedros Ghebreyesus told a conference in Uruguay this week on non-communicable diseases that he had agreed to be a "goodwill ambassador" on the issue.
Mr Tedros, an Ethiopian who became WHO's first African director-general this year, said Mr Mugabe could use the role "to influence his peers in his region".
A WHO spokeswoman confirmed the comments to The Associated Press today.
In his speech, Mr Tedros described Zimbabwe as "a country that places universal health coverage and health promotion at the centre of its policies to provide health care to all."
Two dozen organisations, including the World Heart Federation, released a statement slamming the appointment, saying health officials were "shocked and deeply concerned" and citing his "long track record of human rights violations".
The groups said they had raised their concerns with Mr Tedros on the sidelines of the conference, to no avail.
The southern African nation once was known as the region's prosperous breadbasket.
But in 2008, the charity Physicians for Human Rights released a report documenting failures in Zimbabwe's health system, saying that Mr Mugabe's policies had led to a man-made crisis.
"The government of Robert Mugabe presided over the dramatic reversal of its population's access to food, clean water, basic sanitation and health care," the group concluded.
"The Mugabe regime has used any means at its disposal, including politicising the health sector, to maintain its hold on power."
The report said Mr Mugabe's policies led directly to "the shuttering of hospitals and clinics, the closing of its medical school and the beatings of health workers".
The US in 2003 imposed targeted sanctions, a travel ban and an asset freeze against Mugabe and close associates, citing his government's rights abuses and evidence of electoral fraud.
UN agencies typically choose celebrities as ambassadors to draw attention to issues of concern, but they hold little actual power.
Last year, the UN dropped the superhero Wonder Woman as an ambassador for "empowering girls and women" after the decision drew widespread criticism.