Ethiopia's Tedros Adhanom was elected as the new head of the powerful World Health Organization on Tuesday, vowing to shake up an agency seen as needing major reform.

The former Ethiopian minister beat out Britain's David Nabarro and Sania Nishtar of Pakistan in the race to lead the UN's public health body.

The result was confirmed in a statement by the WHO after three rounds of voting on Tuesday.

Tedros, a 52-year-old malaria specialist, will take over on July 1, succeeding Margaret Chan, a Hong Kong native whose decade-long tenure was marred by the agency's fiercely criticised response to the Ebola epidemic in west Africa.

In his final pitch to member-states before ballots were cast, Tedros vowed to staff the WHO with "a world-class workforce" while introducing strict accountability measures, which critics say have been sorely lacking at the Geneva-based agency.

He listed delivering universal healthcare, especially to the world's most impoverished, as his top priority.

Tedros said he refused "to accept that people should die because they are poor."

Ebola scars

The WHO is perhaps the most influential United Nations agency, charged with emergency response and shaping baseline policies for treatment of major health challenges.

The agency was broadly accused of failing the major test that followed the December 2013 Ebola outbreak, missing key warnings about the severity of an epidemic that ultimately killed more than 11,000 people.

Health officials, including from Washington, a key WHO donor, said the agency's new leadership needed to get right.

"We know that the next health emergency is not a question of 'if' but 'when'", US health secretary Tom Price said in Geneva earlier Tuesday.

"When it happens the world will turn to the WHO for guidance and for leadership. We need to be sure it is up to the task," he told the Swiss Press Club.

Tedros vowed to lead "robust responses to the health crises to come".

An African victory

Tedros will be the first African to lead the WHO and had unanimous backing from the African Union, which claimed that the continent deserved a shot to lead the agency.

Nabarro, who had strong support from his native Britain and touted his decades of experience within the UN system, ultimately failed to persuade voters that the agency needed an insider in its top job.

Nishtar, a former Pakistani health minister, won praise for a strong campaign but was always viewed a long shot.

Tuesday marked the first time that the WHO's 194-member states got to choose the agency's leader.

Previously the executive committee offered just one candidate for states to rubber stamp.

'Big changes' needed

The WHO has already initiated a range of reforms since it faced crushing criticism over its response to the Ebola crisis, but experts say the new chief still faces a huge task.

"We need WHO to be more effective than it is today," the director of Harvard University's Global Health Institute, Ashish Jha, said at the Swiss Press Club event.

Mark Dybul, who heads the Global Fund To Fight AIDS, Tuberculosis and Malaria, said that Chan had "laid the foundations" for improvements but that "big, big changes need to be made".

He underscored "massive" coordination problems between regional offices and the agency's Geneva headquarters.

This was identified as a significant issue in the Ebola crisis, when the African office in Brazzaville was accused of not sounding the alarm.

Impressive record

Tedros earned a doctorate from the University of Nottingham in Britain before being appointed Ethiopia's in 2005.

He oversaw a drive to expand basic healthcare by building thousands of new clinics and boosting community-based health services.

"I am astonished when I think of the path my life has taken," he said before Tuesday's result.

© 2017 AFP