The UK Government has led the criticism of the World Health Organisation (WHO) after it named Zimbabwean President Robert Mugabe a “goodwill ambassador”.

A spokesman said the United Nations agency’s decision was “surprising and disappointing” and risked “overshadowing work undertaken globally by the WHO”.

WHO’s director-general Tedros Ghebreyesus said he was “honoured to announce” the 93-year-old would serve as an ambassador to help tackle non-communicable diseases such as heart attacks, strokes and asthma across Africa.

Speaking at a conference in Uruguay, Dr Tedros described Zimbabwe as “a country that places universal health coverage and health promotion at the centre of its policies to provide healthcare to all” and said Mr Mugabe could “influence his peers in his region”.

But activists inside the country said it was “absurd” to give the role to Mr Mugabe, who has been accused of ruining his country’s health system and regularly flies abroad for his own medical treatment.

Human rights and health groups also pointed to Mr Mugabe’s “long track record of human rights violations”.

Mr Mugabe has been accused of violent repression, election rigging, and presiding over economic ruin during his 37 years as Zimbabwean leader. He has also been blamed for a health crisis that has pushed doctors to strike and left hospitals without medicine.

“Given Mugabe’s appalling human rights record, calling him a goodwill ambassador for anything embarrasses WHO and Dr Tedros,” said Iain Levine, a Human Rights Watch director.

Hillel Neuer, executive director of the Geneva-based group UN Watch, described Mr Mugabe’s appointment as “sickening”.

“The government of Robert Mugabe has brutalised human rights activists, crushed democracy dissidents, and turned the breadbasket of Africa and its health system into a basket-case,” he said. “The notion that the UN should now spin this country as a great supporter of health is, frankly, sickening.”

The Government has complained to the WHO about Mr Mugabe’s appointment.

The UK, the European Union and the US each impose targeted sanctions on Zimbabwe and travel bans and asset freezes on Mr Mugabe, citing his government’s rights abuses and evidence of electoral fraud.

“President Mugabe’s appointment is surprising and disappointing, particularly in light of the current US and EU sanctions against him,” said a UK Government spokesman.

He added: “We have registered our concerns with WHO director-general Dr Tedros Adhanom Ghebreyesus. Although Mugabe will not have an executive role, his appointment risks overshadowing the work undertaken globally by the WHO on non-communicable diseases.”

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The Movement for Democratic Change, the main opposition party in Zimbabwe, described the appointment as “laughable”.

“The Zimbabwe health delivery system is in a shambolic state, it is an insult,” spokesman Obert Gutu told AFP. “Mugabe trashed our health delivery system. He and his family go outside of the country for treatment in Singapore after he allowed our public hospitals to collapse.”

Zimbabwean activists said Mr Mugabe had left the country’s health system “in tatters” and voiced incredulity at the appointment.

Salani Mutseyami, a spokeswoman for the campaign groups Zimbabwe Vigil and Restoration of Human Rights, told the Daily Telegraph: “That is absolutely absurd. It shows the lack of interest that the UN might have towards what is really going on in Zimbabwe.”

Twenty-six health bodies from around the world, including the World Heart Federation, Action Against Smoking and Cancer Research UK, released a joint statement condemning Mr Mugabe’s new role.

They said health officials were “shocked and deeply concerned to hear of this appointment, given President Mugabe’s long track record of human rights violations and undermining the dignity of human beings”.

The groups said they had raised their concerns with Mr Tedros on the sidelines of the conference, which was attended by Mr Mugabe.

Zimbabwe was once one of Africa’s most prosperous nations but suffered a dramatic decline under Mr Mugabe’s rule.

In 2008, the charity Physicians for Human Rights released a report documenting failures in Zimbabwe’s health system and said the president’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 and European Union have each imposed targeted sanctions, travel bans and asset freezes on Mr Mugabe and close associates, citing his government’s rights abuses and evidence of electoral fraud.