The International Labour Organization will pick its next boss on Friday, with the possibility it could place a woman or an African at the helm for the first time.
Five candidates are in the running to succeed British trade unionist Guy Ryder, who will step down at the end of September, after two terms and 10 years in the job.
Former French labour minister Muriel Penicaud is also said to have a good shot, with backing from European countries.
Also in the running are South Korea's ex-foreign minister Kang Kyung-wha, entrepreneur Mthunzi Mdwaba of South Africa, and ILO deputy Greg Vines of Australia.
Whoever wins, a change is on the cards: the ILO's 10 chiefs so far have all been men from Europe or the Americas.
Founded in 1919, the ILO is the oldest specialised UN agency, with 187 member states, which are, uniquely in the UN system, represented by governments, employers and workers.
Headquartered in a vast 1960s-designed rationalist rectangular block, the ILO aims to promote rights at work, encourage good employment opportunities, enhance social protection and strengthen dialogue on work-related issues.
The next ILO chief will have their work cut out for them, as the 103-year-old organisation strives to adapt its norms to a world of work rapidly transforming due to evolving technologies.
The Covid-19 pandemic has only sped up those changes, leading to the rapid uptake of virtual technologies to enable remote working.
Friday's vote will take place behind closed doors, and only members of ILO's governing body are permitted to participate.
The vote, by secret ballot, will kick off at 10:00 am (0900 GMT), and it could take several rounds of gradually eliminating the candidate with the least votes before one candidate secures a majority.
The governing body counts 56 members, with half of them representing governments, and a quarter each representing employers and workers.
Ten of the government slots are permanently held by countries of significant industrial importance: Brazil, Britain, China, France, Germany, India, Italy, Japan, the United States, and Russia.
That permanent seat means that Russia will be permitted to participate in
Friday's vote, despite an ILO decision earlier this week to suspend all technical cooperation with the country until it halts its war in Ukraine.
Going in, it remains unclear which of the candidates has the backing needed to secure a win.
Houngbo of Togo has been seen in the lead after the African Union threw its weight behind him.
Currently head of the Rome-based International Fund for Agricultural Development (IFAD), he also enjoys strong backing on the labour side.
He has held several high level positions within the UN system previously, including as finance director at the UN Development Programme (UNDP) and as deputy director-general of ILO itself, from 2013-2017.
The International Organisation of Employers (IOE) has meanwhile come out in favour of Mdwaba of South Africa, who currently serves on the ILO board.
If he gets the nod -- not a likely outcome, according to observers -- he would be the first ever representative of the employer side to take the ILO helm.
Penicaud, who served as France's labour minister from 2017 to 2020, has meanwhile faced strong union criticism over her role initiating some of President Emmanuel Macron's major social reforms, including changing labour laws and unemployment insurance.
She was also instrumental in promoting apprenticeships in France and pushing for more gender equality in the workplace.
Kang, who served as South Korea's first female foreign minister, in post from 2017 to February last year, has a broad UN career behind her, including as policy advisor to UN Secretary-General Antonio Guterres. But she has faced criticism for lacking labour experience.
Vines, who has served as ILO deputy director-general since 2012 and previously represented Australian unions, could meanwhile provide continuity after Ryder, something seen as a weakness for some of the other candidates.